TypeScript名词解释系列：tsconfg中的target，module和moduleResolution

tsconfg中的target，module和moduleResolution

target

就是TypeScript文件编译后生成的javascript文件里的语法应该遵循哪个JavaScript的版本。可选项为："ES5"， "ES6"/ "ES2015"， "ES2016"， "ES2017"或 "ESNext"

module

就是你的TypeScript文件中的module，采用何种方式实现，可选项为："None"， "CommonJS"， "AMD"， "System"， "UMD"， "ES6"或 "ES2015"。具体每一个module的定义，请参考链接：

https://medium.com/computed-comparisons/commonjs-vs-amd-vs-requirejs-vs-es6-modules-2e814b114a0b

moduleResolution

就是告诉TypeScript编译器，采用何种方式解析（也就是查找）TypeScript文件中依赖的模块的位置，可选项为：Classic和Node，具体定义，请参考链接：

https://www.tslang.cn/docs/handbook/module-resolution.html

 target举例

ts文件中的源代码

async function helloWorld(): Promise<string> {
    const res = await fetch('/static/data.json');
    const txt = await res.text();
    return txt;
}
(async ()=>{
    const txt = await helloWorld()
    console.log(`async func: `, txt)
})()

target设置成es5

var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
var __generator = (this && this.__generator) || function (thisArg, body) {
    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
    function verb(n) { return function (v) { return step([n, v]); }; }
    function step(op) {
        if (f) throw new TypeError("Generator is already executing.");
        while (_) try {
            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
            if (y = 0, t) op = [op[0] & 2, t.value];
            switch (op[0]) {
                case 0: case 1: t = op; break;
                case 4: _.label++; return { value: op[1], done: false };
                case 5: _.label++; y = op[1]; op = [0]; continue;
                case 7: op = _.ops.pop(); _.trys.pop(); continue;
                default:
                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
                    if (t[2]) _.ops.pop();
                    _.trys.pop(); continue;
            }
            op = body.call(thisArg, _);
        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
    }
};
var _this = this;
function helloWorld() {
    return __awaiter(this, void 0, void 0, function () {
        var res, txt;
        return __generator(this, function (_a) {
            switch (_a.label) {
                case 0: return [4 /*yield*/, fetch('/static/data.json')];
                case 1:
                    res = _a.sent();
                    return [4 /*yield*/, res.text()];
                case 2:
                    txt = _a.sent();
                    return [2 /*return*/, txt];
            }
        });
    });
}
(function () { return __awaiter(_this, void 0, void 0, function () {
    var txt;
    return __generator(this, function (_a) {
        switch (_a.label) {
            case 0: return [4 /*yield*/, helloWorld()];
            case 1:
                txt = _a.sent();
                console.log("async func: ", txt);
                return [2 /*return*/];
        }
    });
}); })();

target设置成es6

var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
    function adopt(value) { return value instanceof P ? value : new P(function (resolve) { resolve(value); }); }
    return new (P || (P = Promise))(function (resolve, reject) {
        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
        function step(result) { result.done ? resolve(result.value) : adopt(result.value).then(fulfilled, rejected); }
        step((generator = generator.apply(thisArg, _arguments || [])).next());
    });
};
function helloWorld() {
    return __awaiter(this, void 0, void 0, function* () {
        const res = yield fetch('/static/data.json');
        const txt = yield res.text();
        return txt;
    });
}
(() => __awaiter(this, void 0, void 0, function* () {
    const txt = yield helloWorld();
    console.log(`async func: `, txt);
}))();

target设置成esnext

async function helloWorld() {
    const res = await fetch('/static/data.json');
    const txt = await res.text();
    return txt;
}
(async () => {
    const txt = await helloWorld();
    console.log(`async func: `, txt);
})();

module举例

ts文件中的源代码

设置为commonjs

设置为es6