gulp-path-alias/lib/index.js

path alias

"use strict";
var __importDefault = (this && this.__importDefault) || function (mod) {
    return (mod && mod.__esModule) ? mod : { "default": mod };
};
const path_1 = __importDefault(require("path"));
const through2_1 = __importDefault(require("through2"));
const replacestream_1 = __importDefault(require("replacestream"));
const slash_1 = __importDefault(require("slash"));
const prefixPatternMap = {
    js: 'import\\s*[^\'"]*\\(?|from|require\\s*\\(',
    // poster: wxml
    xml: 'src=|url=|poster=|href=',
    css: '@import\\s*|url\\s*\\(',
};
/* 全匹配的正则规则 */
const exactMatchPattern = /\$$/;
/**
 * 编码别名替换项
 * eg. '/' -> '\\/'
 */
function encodeAliasString(alias) {
    return alias.replace('/', '\\/');
}
/* 获取匹配前缀正则字符串 */
function getPrefixPatternString(prefixPatten) {
    return `(?:(${prefixPatten})\\s*['"]?\\s*)`;
}
/* 获取匹配后缀正则字符串 */
function getSuffixPatternString(exactMatch = false) {
    const suffixPattern = '[\'"]|\\s*\\)';
    // 全匹配时，后面没有内容，拿掉斜线
    return exactMatch ? suffixPattern : `\\/|${suffixPattern}`;
}
/* 获取匹配主体和后缀的正则字符串 */
function getRemainPatternString(aliasKey, exactMatch) {
    const _aliasKey = exactMatch ? aliasKey.replace(exactMatchPattern, '') : aliasKey;
    return `(?<alias>${_aliasKey})(${getSuffixPatternString(exactMatch)})`;
}
/* 获取相对路径 */
function relative(from, to) {
    const relativePath = slash_1.default(path_1.default.relative(from, to));
    if (!relativePath) {
        return '.';
    }
    return !/^\./.test(relativePath) ? `./${relativePath}` : relativePath;
}
// 100000 rows * 100 columns -> 248ms
function replaceAll(file, dirname, aliasList) {
    const ext = path_1.default.extname(file.relative);
    const isStream = file.isStream();
    /* 根据后缀名获得前缀正则字符串，降低复杂度 */
    let prefixPatternString;
    switch (ext) {
        // js
        case '.js':
        case '.ts':
        case '.wxs':
            prefixPatternString = getPrefixPatternString(prefixPatternMap.js);
            break;
        // css
        case '.css':
        case '.less':
        case '.scss':
        case '.sass':
        case '.styl':
        case '.stylus':
        case '.wxss':
            prefixPatternString = getPrefixPatternString(prefixPatternMap.css);
            break;
        // xml
        case '.html':
        case '.wxml':
            prefixPatternString = getPrefixPatternString(prefixPatternMap.xml);
            break;
        case '.jsx':
        case '.tsx':
        default:
            prefixPatternString = getPrefixPatternString(Object.keys(prefixPatternMap)
                .map((k) => prefixPatternMap[k])
                .join('|'));
            break;
    }
    aliasList.forEach(({ aliasKey, aliasValue }) => {
        const isExactMatch = exactMatchPattern.test(aliasKey);
        const remainPatternString = getRemainPatternString(aliasKey, isExactMatch);
        const sentenceReg = new RegExp(`${prefixPatternString}${remainPatternString}`, 'gm');
        const replacer = (match, ...args) => {
            const group = args.pop();
            const { alias } = group;
            /* 如果替换路径是相对路径不使用 relative 路径替换，而是直接替换 */
            const replaceStr = path_1.default.isAbsolute(aliasValue) ? relative(dirname, aliasValue) : aliasValue;
            return match.replace(alias, replaceStr);
        };
        /* 先确定文件中匹配的语句，再替换其中所有匹配的 alias */
        if (isStream) {
            file.contents = file.contents.pipe(replacestream_1.default(sentenceReg, replacer));
        }
        else {
            file.contents = Buffer.from(String(file.contents).replace(sentenceReg, replacer));
        }
    });
    return file;
}
/**
 *
 * @param options
 */
function alias(options = {}) {
    const _options = Object.assign({ cwd: process.cwd(), paths: {} }, options);
    const { paths } = _options;
    const isEmptyAlias = !Object.keys(paths).length;
    /* 初始化 aliasList，全局使用，避免重复计算 */
    const aliasList = Object.keys(paths)
        /* 全匹配的需要优先替换，放在前面 */
        .sort((a) => (exactMatchPattern.test(a) ? -1 : 1))
        .map((aliasKey) => {
        /* 替换斜线，否则生成 pattern 时会出错 */
        const encodeKey = encodeAliasString(aliasKey);
        return {
            aliasKey: encodeKey,
            aliasValue: paths[aliasKey],
        };
    });
    return through2_1.default.obj(function (file, _, cb) {
        const dirname = path_1.default.dirname(file.path);
        if (file.isNull() || isEmptyAlias) {
            return cb(null, file);
        }
        file = replaceAll(file, dirname, aliasList);
        cb(null, file);
    });
}
module.exports = alias;