pathTemplate.js 6.18 KB
"use strict";
/*
 * Copyright 2019 Google LLC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
Object.defineProperty(exports, "__esModule", { value: true });
/*
 * Path template utility.
 */
const has = require("lodash.has");
const util = require("util");
const extras = require("./parserExtras");
const parser = require('./pathTemplateParser');
class PathTemplate {
    /**
     * @param {String} data the of the template
     *
     * @constructor
     */
    constructor(data) {
        this.parseResult = extras.finishParse(parser.parse(data));
    }
    get size() {
        return this.parseResult.size;
    }
    get segments() {
        return this.parseResult.segments;
    }
    /**
     * Matches a fully-qualified path template string.
     *
     * @param {String} path a fully-qualified path template string
     * @return {Object} contains const names matched to binding values
     * @throws {TypeError} if path can't be matched to this template
     */
    match(path) {
        const pathSegments = path.split('/');
        const bindings = {};
        let segmentCount = this.size;
        let current;
        let index = 0;
        this.segments.forEach(segment => {
            if (index > pathSegments.length) {
                return;
            }
            if (segment.kind === extras.BINDING) {
                current = segment.literal;
            }
            else if (segment.kind === extras.TERMINAL) {
                if (segment.literal === '*') {
                    bindings[current] = pathSegments[index];
                    index += 1;
                }
                else if (segment.literal === '**') {
                    const size = pathSegments.length - segmentCount + 1;
                    segmentCount += size - 1;
                    bindings[current] = pathSegments.slice(index, index + size).join('/');
                    index += size;
                }
                else if (segment.literal === pathSegments[index]) {
                    index += 1;
                }
                else {
                    const msg = util.format("mismatched literal (index=%d): '%s' != '%s'", index, segment.literal, pathSegments[index]);
                    throw new TypeError(msg);
                }
            }
        });
        if (index !== pathSegments.length || index !== segmentCount) {
            const msg = util.format('match error: could not instantiate a path template from %s', path);
            throw new TypeError(msg);
        }
        return bindings;
    }
    /**
     * Renders a path template using the provided bindings.
     *
     * @param {Object} bindings a mapping of const names to binding strings
     * @return {String} a rendered representation of the path template
     * @throws {TypeError} if a key is missing, or if a sub-template cannot be
     *   parsed
     */
    render(bindings) {
        const out = [];
        let inABinding = false;
        this.segments.forEach(segment => {
            if (segment.kind === extras.BINDING) {
                if (!has(bindings, segment.literal)) {
                    const msg = util.format('Value for key %s is not provided in %s', segment.literal, bindings);
                    throw new TypeError(msg);
                }
                const tmp = new PathTemplate(bindings[segment.literal]);
                Array.prototype.push.apply(out, tmp.segments);
                inABinding = true;
            }
            else if (segment.kind === extras.END_BINDING) {
                inABinding = false;
            }
            else if (inABinding) {
                return;
            }
            else {
                out.push(segment);
            }
        });
        const result = formatSegments(out);
        this.match(result);
        return result;
    }
    /**
     * Renders the path template.
     *
     * @return {string} contains const names matched to binding values
     */
    inspect() {
        return formatSegments(this.segments);
    }
}
exports.PathTemplate = PathTemplate;
/**
 * Creates the string representattion for the segments.
 * @param {Object[]} segments - The array of segments.
 * @return {string} - A string representing segments in the path template
 *   format.
 */
function formatSegments(segments) {
    let out = '';
    let slash = true;
    segments.forEach(segment => {
        if (segment.kind === extras.TERMINAL) {
            if (slash) {
                out += '/';
            }
            out += segment.literal;
            return;
        }
        slash = true;
        if (segment.kind === extras.BINDING) {
            out += '/{' + segment.literal + '=';
            slash = false;
        }
        else {
            out += segment.literal + '}';
        }
    });
    return out.substring(1);
}
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