coverage-shaker/dist/lib/shake.js

Minify JavaScript code from chrome/puppeteer coverage report. tree shaking.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.shake = void 0;
const core_1 = require("@babel/core");
const uglify_js_1 = require("uglify-js");
function shake(coverage) {
    let cursor = 0;
    const result = core_1.transformSync(coverage.text, {
        minified: true,
        comments: false,
        plugins: [{
                name: "coverage-shaker",
                visitor: {
                    BlockStatement(path) {
                        const { start, end } = path.node;
                        if (!start || !end) {
                            // 异常情况不处理
                            return;
                        }
                        while (cursor < coverage.ranges.length) {
                            const range = coverage.ranges[cursor];
                            if (range.end <= start) {
                                // 说明range还没跟上本代码片段的脚步
                                // 需要看看下一个range是否有交叉了
                                cursor++;
                                continue;
                            }
                            if (range.start >= end) {
                                // 说明代码已经执行到后面去了，本block没有执行过
                                path.node.body = [];
                                // 函数里都没内容了，函数参数留着也没用了
                                const parent = path.parent;
                                if (parent.params) {
                                    parent.params = [];
                                }
                            }
                            // 剩下的情况都说明中间的代码执行过了，不能删除
                            return;
                        }
                    },
                }
            }]
    });
    if (result && result.code) {
        // 不知道为啥要两次才能压缩干净
        return uglify_js_1.minify(uglify_js_1.minify(result.code).code).code;
    }
    return '';
}
exports.shake = shake;
function parse(coverages, files = []) {
    const shaked_code = [];
    const sources = files.length > 0 ? files : coverages.map(c => c.url);
    for (let coverage of coverages) {
        for (let file of sources) {
            if (coverage.url.endsWith(file)) {
                shaked_code.push({
                    url: coverage.url,
                    code: shake(coverage)
                });
            }
        }
    }
    return shaked_code;
}
exports.default = parse;
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