168 lines
4.2 KiB
JavaScript
168 lines
4.2 KiB
JavaScript
'use strict';
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var escapeRegExp = require('escape-string-regexp');
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var SIMPLE_PLACEHOLDER_RX = /^\[(id|name|file|query|filebase)]/i;
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var HASH_PLACEHOLDER_RX = /^\[((?:full)?(?:chunk)?hash)(?::(\d+))?]/i;
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var templateCache = Object.create(null);
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module.exports = function createTemplate(str) {
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if (!templateCache[str]) {
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templateCache[str] = new PathTemplate(str);
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}
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return templateCache[str];
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};
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function PathTemplate(template) {
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this.template = template;
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this.fields = parseTemplate(template);
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this.matcher = createTemplateMatcher(this.fields);
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}
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PathTemplate.prototype = {
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constructor: PathTemplate,
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/**
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* Returns whether the given path matches this template.
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*
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* @param String data
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*/
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matches: function matches(path) {
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return this.matcher.test(path);
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},
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/**
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* Applies data to this template and outputs a filename.
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*
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* @param Object data
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*/
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resolve: function resolve(data) {
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return this.fields.reduce(function (output, field) {
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var replacement = '';
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var placeholder = field.placeholder;
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var width = field.width;
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if (field.prefix) {
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output += field.prefix;
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}
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if (placeholder) {
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replacement = data[placeholder] || '';
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if (width && (placeholder === 'hash' || placeholder === 'fullhash' || placeholder === 'chunkhash')) {
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replacement = replacement.slice(0, width);
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}
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output += replacement;
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}
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return output;
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}, '');
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}
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/**
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* Loop over the template string and return an array of objects in the form:
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* {
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* prefix: 'literal text',
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* placeholder: 'replacement field name'
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* [, width: maximum hash length for hash & chunkhash placeholders]
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* }
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*
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* The values in the object conceptually represent a span of literal text followed by a single replacement field.
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* If there is no literal text (which can happen if two replacement fields occur consecutively),
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* then prefix will be an empty string.
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* If there is no replacement field, then the value of placeholder will be null.
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* If the value of placeholder is either 'hash', 'fullhash', or 'chunkhash', then width will be a positive integer.
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* Otherwise it will be left undefined.
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*/
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};function parseTemplate(str) {
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var fields = [];
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var char = '';
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var pos = 0;
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var prefix = '';
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var match = null;
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var input = void 0;
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while (true) {
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// eslint-disable-line no-constant-condition
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char = str[pos];
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if (!char) {
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fields.push({
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prefix: prefix,
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placeholder: null
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});
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break;
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} else if (char === '[') {
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input = str.slice(pos);
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match = SIMPLE_PLACEHOLDER_RX.exec(input);
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if (match) {
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fields.push({
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prefix: prefix,
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placeholder: match[1].toLowerCase()
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});
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pos += match[0].length;
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prefix = '';
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continue;
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}
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match = HASH_PLACEHOLDER_RX.exec(input);
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if (match) {
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fields.push({
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prefix: prefix,
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placeholder: match[1].toLowerCase(),
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width: parseInt(match[2] || 0, 10)
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});
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pos += match[0].length;
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prefix = '';
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continue;
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}
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}
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prefix += char;
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pos++;
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}
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return fields;
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}
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/**
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* Returns a RegExp which, given the replacement fields returned by parseTemplate(),
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* can match a file path against a path template.
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*/
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function createTemplateMatcher(fields) {
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var length = fields.length;
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var pattern = fields.reduce(function (pattern, field, i) {
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if (i === 0) {
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pattern = '^';
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}
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if (field.prefix) {
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pattern += '(' + escapeRegExp(field.prefix) + ')';
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}
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if (field.placeholder) {
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switch (field.placeholder) {
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case 'hash':
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case 'fullhash':
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case 'chunkhash':
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pattern += '[0-9a-fA-F]';
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pattern += field.width ? '{1,' + field.width + '}' : '+';
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break;
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case 'id':
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case 'name':
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case 'file':
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case 'filebase':
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pattern += '.+?';
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break;
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case 'query':
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pattern += '(?:\\?.+?)?';
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break;
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}
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}
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if (i === length - 1) {
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pattern += '$';
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}
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return pattern;
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}, '');
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return new RegExp(pattern);
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} |