380 lines
8.7 KiB
JavaScript
Executable file
380 lines
8.7 KiB
JavaScript
Executable file
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const { SyncHook } = require("tapable");
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/**
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* @typedef {Object} RuleCondition
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* @property {string | string[]} property
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* @property {boolean} matchWhenEmpty
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* @property {function(string): boolean} fn
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*/
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/**
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* @typedef {Object} Condition
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* @property {boolean} matchWhenEmpty
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* @property {function(string): boolean} fn
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*/
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/**
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* @typedef {Object} CompiledRule
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* @property {RuleCondition[]} conditions
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* @property {(Effect|function(object): Effect[])[]} effects
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* @property {CompiledRule[]=} rules
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* @property {CompiledRule[]=} oneOf
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*/
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/**
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* @typedef {Object} Effect
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* @property {string} type
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* @property {any} value
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*/
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/**
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* @typedef {Object} RuleSet
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* @property {Map<string, any>} references map of references in the rule set (may grow over time)
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* @property {function(object): Effect[]} exec execute the rule set
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*/
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class RuleSetCompiler {
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constructor(plugins) {
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this.hooks = Object.freeze({
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/** @type {SyncHook<[string, object, Set<string>, CompiledRule, Map<string, any>]>} */
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rule: new SyncHook([
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"path",
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"rule",
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"unhandledProperties",
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"compiledRule",
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"references"
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])
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});
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if (plugins) {
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for (const plugin of plugins) {
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plugin.apply(this);
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}
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}
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}
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/**
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* @param {object[]} ruleSet raw user provided rules
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* @returns {RuleSet} compiled RuleSet
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*/
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compile(ruleSet) {
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const refs = new Map();
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const rules = this.compileRules("ruleSet", ruleSet, refs);
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/**
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* @param {object} data data passed in
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* @param {CompiledRule} rule the compiled rule
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* @param {Effect[]} effects an array where effects are pushed to
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* @returns {boolean} true, if the rule has matched
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*/
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const execRule = (data, rule, effects) => {
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for (const condition of rule.conditions) {
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const p = condition.property;
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if (Array.isArray(p)) {
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let current = data;
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for (const subProperty of p) {
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if (
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current &&
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typeof current === "object" &&
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Object.prototype.hasOwnProperty.call(current, subProperty)
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) {
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current = current[subProperty];
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} else {
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current = undefined;
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break;
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}
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}
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if (current !== undefined) {
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if (!condition.fn(current)) return false;
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continue;
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}
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} else if (p in data) {
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const value = data[p];
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if (value !== undefined) {
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if (!condition.fn(value)) return false;
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continue;
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}
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}
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if (!condition.matchWhenEmpty) {
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return false;
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}
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}
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for (const effect of rule.effects) {
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if (typeof effect === "function") {
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const returnedEffects = effect(data);
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for (const effect of returnedEffects) {
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effects.push(effect);
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}
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} else {
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effects.push(effect);
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}
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}
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if (rule.rules) {
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for (const childRule of rule.rules) {
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execRule(data, childRule, effects);
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}
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}
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if (rule.oneOf) {
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for (const childRule of rule.oneOf) {
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if (execRule(data, childRule, effects)) {
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break;
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}
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}
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}
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return true;
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};
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return {
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references: refs,
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exec: data => {
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/** @type {Effect[]} */
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const effects = [];
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for (const rule of rules) {
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execRule(data, rule, effects);
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}
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return effects;
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}
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};
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}
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/**
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* @param {string} path current path
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* @param {object[]} rules the raw rules provided by user
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* @param {Map<string, any>} refs references
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* @returns {CompiledRule[]} rules
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*/
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compileRules(path, rules, refs) {
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return rules.map((rule, i) =>
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this.compileRule(`${path}[${i}]`, rule, refs)
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);
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}
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/**
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* @param {string} path current path
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* @param {object} rule the raw rule provided by user
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* @param {Map<string, any>} refs references
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* @returns {CompiledRule} normalized and compiled rule for processing
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*/
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compileRule(path, rule, refs) {
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const unhandledProperties = new Set(
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Object.keys(rule).filter(key => rule[key] !== undefined)
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);
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/** @type {CompiledRule} */
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const compiledRule = {
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conditions: [],
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effects: [],
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rules: undefined,
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oneOf: undefined
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};
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this.hooks.rule.call(path, rule, unhandledProperties, compiledRule, refs);
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if (unhandledProperties.has("rules")) {
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unhandledProperties.delete("rules");
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const rules = rule.rules;
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if (!Array.isArray(rules))
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throw this.error(path, rules, "Rule.rules must be an array of rules");
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compiledRule.rules = this.compileRules(`${path}.rules`, rules, refs);
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}
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if (unhandledProperties.has("oneOf")) {
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unhandledProperties.delete("oneOf");
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const oneOf = rule.oneOf;
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if (!Array.isArray(oneOf))
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throw this.error(path, oneOf, "Rule.oneOf must be an array of rules");
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compiledRule.oneOf = this.compileRules(`${path}.oneOf`, oneOf, refs);
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}
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if (unhandledProperties.size > 0) {
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throw this.error(
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path,
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rule,
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`Properties ${Array.from(unhandledProperties).join(", ")} are unknown`
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);
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}
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return compiledRule;
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}
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/**
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* @param {string} path current path
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* @param {any} condition user provided condition value
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* @returns {Condition} compiled condition
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*/
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compileCondition(path, condition) {
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if (condition === "") {
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return {
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matchWhenEmpty: true,
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fn: str => str === ""
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};
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}
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if (!condition) {
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throw this.error(
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path,
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condition,
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"Expected condition but got falsy value"
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);
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}
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if (typeof condition === "string") {
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return {
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matchWhenEmpty: condition.length === 0,
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fn: str => typeof str === "string" && str.startsWith(condition)
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};
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}
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if (typeof condition === "function") {
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try {
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return {
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matchWhenEmpty: condition(""),
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fn: condition
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};
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} catch (err) {
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throw this.error(
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path,
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condition,
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"Evaluation of condition function threw error"
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);
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}
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}
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if (condition instanceof RegExp) {
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return {
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matchWhenEmpty: condition.test(""),
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fn: v => typeof v === "string" && condition.test(v)
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};
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}
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if (Array.isArray(condition)) {
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const items = condition.map((c, i) =>
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this.compileCondition(`${path}[${i}]`, c)
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);
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return this.combineConditionsOr(items);
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}
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if (typeof condition !== "object") {
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throw this.error(
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path,
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condition,
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`Unexpected ${typeof condition} when condition was expected`
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);
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}
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const conditions = [];
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for (const key of Object.keys(condition)) {
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const value = condition[key];
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switch (key) {
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case "or":
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if (value) {
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if (!Array.isArray(value)) {
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throw this.error(
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`${path}.or`,
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condition.and,
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"Expected array of conditions"
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);
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}
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conditions.push(this.compileCondition(`${path}.or`, value));
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}
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break;
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case "and":
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if (value) {
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if (!Array.isArray(value)) {
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throw this.error(
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`${path}.and`,
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condition.and,
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"Expected array of conditions"
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);
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}
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let i = 0;
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for (const item of value) {
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conditions.push(this.compileCondition(`${path}.and[${i}]`, item));
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i++;
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}
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}
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break;
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case "not":
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if (value) {
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const matcher = this.compileCondition(`${path}.not`, value);
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const fn = matcher.fn;
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conditions.push({
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matchWhenEmpty: !matcher.matchWhenEmpty,
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fn: v => !fn(v)
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});
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}
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break;
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default:
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throw this.error(
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`${path}.${key}`,
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condition[key],
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`Unexpected property ${key} in condition`
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);
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}
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}
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if (conditions.length === 0) {
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throw this.error(
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path,
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condition,
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"Expected condition, but got empty thing"
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);
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}
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return this.combineConditionsAnd(conditions);
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}
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/**
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* @param {Condition[]} conditions some conditions
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* @returns {Condition} merged condition
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*/
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combineConditionsOr(conditions) {
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if (conditions.length === 0) {
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return {
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matchWhenEmpty: false,
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fn: () => false
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};
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} else if (conditions.length === 1) {
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return conditions[0];
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} else {
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return {
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matchWhenEmpty: conditions.some(c => c.matchWhenEmpty),
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fn: v => conditions.some(c => c.fn(v))
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};
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}
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}
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/**
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* @param {Condition[]} conditions some conditions
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* @returns {Condition} merged condition
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*/
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combineConditionsAnd(conditions) {
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if (conditions.length === 0) {
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return {
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matchWhenEmpty: false,
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fn: () => false
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};
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} else if (conditions.length === 1) {
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return conditions[0];
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} else {
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return {
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matchWhenEmpty: conditions.every(c => c.matchWhenEmpty),
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fn: v => conditions.every(c => c.fn(v))
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};
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}
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}
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/**
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* @param {string} path current path
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* @param {any} value value at the error location
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* @param {string} message message explaining the problem
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* @returns {Error} an error object
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*/
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error(path, value, message) {
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return new Error(
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`Compiling RuleSet failed: ${message} (at ${path}: ${value})`
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);
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}
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}
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module.exports = RuleSetCompiler;
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