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/*
MIT License http://www.opensource.org/licenses/mit-license.php
Author Tobias Koppers @sokra
*/
"use strict";
const quoteMeta = str => {
return str.replace(/[-[\]\\/{}()*+?.^$|]/g, "\\$&");
};
const toSimpleString = str => {
if (`${+str}` === str) {
return str;
}
return JSON.stringify(str);
};
/**
* @param {Record<string|number, boolean>} map value map
* @returns {boolean|(function(string): string)} true/false, when unconditionally true/false, or a template function to determine the value at runtime
*/
const compileBooleanMatcher = map => {
const positiveItems = Object.keys(map).filter(i => map[i]);
const negativeItems = Object.keys(map).filter(i => !map[i]);
if (positiveItems.length === 0) return false;
if (negativeItems.length === 0) return true;
return compileBooleanMatcherFromLists(positiveItems, negativeItems);
};
/**
* @param {string[]} positiveItems positive items
* @param {string[]} negativeItems negative items
* @returns {function(string): string} a template function to determine the value at runtime
*/
const compileBooleanMatcherFromLists = (positiveItems, negativeItems) => {
if (positiveItems.length === 0) return () => "false";
if (negativeItems.length === 0) return () => "true";
if (positiveItems.length === 1)
return value => `${toSimpleString(positiveItems[0])} == ${value}`;
if (negativeItems.length === 1)
return value => `${toSimpleString(negativeItems[0])} != ${value}`;
const positiveRegexp = itemsToRegexp(positiveItems);
const negativeRegexp = itemsToRegexp(negativeItems);
if (positiveRegexp.length <= negativeRegexp.length) {
return value => `/^${positiveRegexp}$/.test(${value})`;
} else {
return value => `!/^${negativeRegexp}$/.test(${value})`;
}
};
const popCommonItems = (itemsSet, getKey, condition) => {
const map = new Map();
for (const item of itemsSet) {
const key = getKey(item);
if (key) {
let list = map.get(key);
if (list === undefined) {
list = [];
map.set(key, list);
}
list.push(item);
}
}
const result = [];
for (const list of map.values()) {
if (condition(list)) {
for (const item of list) {
itemsSet.delete(item);
}
result.push(list);
}
}
return result;
};
const getCommonPrefix = items => {
let prefix = items[0];
for (let i = 1; i < items.length; i++) {
const item = items[i];
for (let p = 0; p < prefix.length; p++) {
if (item[p] !== prefix[p]) {
prefix = prefix.slice(0, p);
break;
}
}
}
return prefix;
};
const getCommonSuffix = items => {
let suffix = items[0];
for (let i = 1; i < items.length; i++) {
const item = items[i];
for (let p = item.length - 1, s = suffix.length - 1; s >= 0; p--, s--) {
if (item[p] !== suffix[s]) {
suffix = suffix.slice(s + 1);
break;
}
}
}
return suffix;
};
const itemsToRegexp = itemsArr => {
if (itemsArr.length === 1) {
return quoteMeta(itemsArr[0]);
}
const finishedItems = [];
// merge single char items: (a|b|c|d|ef) => ([abcd]|ef)
let countOfSingleCharItems = 0;
for (const item of itemsArr) {
if (item.length === 1) {
countOfSingleCharItems++;
}
}
// special case for only single char items
if (countOfSingleCharItems === itemsArr.length) {
return `[${quoteMeta(itemsArr.sort().join(""))}]`;
}
const items = new Set(itemsArr.sort());
if (countOfSingleCharItems > 2) {
let singleCharItems = "";
for (const item of items) {
if (item.length === 1) {
singleCharItems += item;
items.delete(item);
}
}
finishedItems.push(`[${quoteMeta(singleCharItems)}]`);
}
// special case for 2 items with common prefix/suffix
if (finishedItems.length === 0 && items.size === 2) {
const prefix = getCommonPrefix(itemsArr);
const suffix = getCommonSuffix(
itemsArr.map(item => item.slice(prefix.length))
);
if (prefix.length > 0 || suffix.length > 0) {
return `${quoteMeta(prefix)}${itemsToRegexp(
itemsArr.map(i => i.slice(prefix.length, -suffix.length || undefined))
)}${quoteMeta(suffix)}`;
}
}
// special case for 2 items with common suffix
if (finishedItems.length === 0 && items.size === 2) {
const it = items[Symbol.iterator]();
const a = it.next().value;
const b = it.next().value;
if (a.length > 0 && b.length > 0 && a.slice(-1) === b.slice(-1)) {
return `${itemsToRegexp([a.slice(0, -1), b.slice(0, -1)])}${quoteMeta(
a.slice(-1)
)}`;
}
}
// find common prefix: (a1|a2|a3|a4|b5) => (a(1|2|3|4)|b5)
const prefixed = popCommonItems(
items,
item => (item.length >= 1 ? item[0] : false),
list => {
if (list.length >= 3) return true;
if (list.length <= 1) return false;
return list[0][1] === list[1][1];
}
);
for (const prefixedItems of prefixed) {
const prefix = getCommonPrefix(prefixedItems);
finishedItems.push(
`${quoteMeta(prefix)}${itemsToRegexp(
prefixedItems.map(i => i.slice(prefix.length))
)}`
);
}
// find common suffix: (a1|b1|c1|d1|e2) => ((a|b|c|d)1|e2)
const suffixed = popCommonItems(
items,
item => (item.length >= 1 ? item.slice(-1) : false),
list => {
if (list.length >= 3) return true;
if (list.length <= 1) return false;
return list[0].slice(-2) === list[1].slice(-2);
}
);
for (const suffixedItems of suffixed) {
const suffix = getCommonSuffix(suffixedItems);
finishedItems.push(
`${itemsToRegexp(
suffixedItems.map(i => i.slice(0, -suffix.length))
)}${quoteMeta(suffix)}`
);
}
// TODO further optimize regexp, i. e.
// use ranges: (1|2|3|4|a) => [1-4a]
const conditional = finishedItems.concat(Array.from(items, quoteMeta));
if (conditional.length === 1) return conditional[0];
return `(${conditional.join("|")})`;
};
compileBooleanMatcher.fromLists = compileBooleanMatcherFromLists;
compileBooleanMatcher.itemsToRegexp = itemsToRegexp;
module.exports = compileBooleanMatcher;