node.js - 如何将Gulp的process.env.NODE_ENV传递给Webpack？

我有一个gulpfile，在其中创建了webpackDevServer来实时更新我的​​js代码。我在gulpfile中设置了一个process.env.NODE_ENV变量，但是由于某种原因，webpack看不到它-它是未定义的。

这是我的gulpfile.js的相关部分：

gulp.task("watch", ["_set-env:dev"], function() {
    // modify default webpack configuration for Development Server
    var webpackDevConfig = Object.create(webpackConfig);
    webpackDevConfig.devtool = "eval";
    webpackDevConfig.debug = "true";

    new webpackDevServer(webpack(webpackDevConfig), {
        proxy: {
            "/api/*": {target: "http://localhost:8000", secure: false},
            "/static/*": {target: "http://localhost:8000", secure: false},
            "/media/*": {target: "http://localhost:8000", secure: false}
        }
    }).listen(8001, "localhost", function (err) {
        if (err) throw new gutil.PluginError("webpack-dev-server", err);
        gutil.log("[webpack-dev-server]", "http://localhost:8001" + webpackDevConfig.output.publicPath);
    });
});

gulp.task("_set-env:dev", function() {
    gutil.log("set-env", "ENV => development");
    genv({
        vars: {
            NODE_ENV: "development"
        }
    });
});

然后在webpack中，我检查它的值，并且它是未定义的：

const webpack = require("webpack");
const path = require("path");

const HtmlWebpackPlugin = require("html-webpack-plugin");
const ExtractTextPlugin = require("extract-text-webpack-plugin");
...
const environmentsFile = path.join(__dirname, "/environments.json");
const nodeModulesPath = path.join(__dirname, "/node_modules");
const bowerComponentsPath = path.join(__dirname, "/bower_components");

console.log("!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
console.log(process.env.NODE_ENV);

const webpackConfig = {
    entry: {
        app: ["app.js"]
    },

在控制台上，我看到：

$ gulp watch
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
undefined
[22:28:34] Using gulpfile ~/Documents/frontend/gulpfile.js
[22:28:34] Starting '_set-env:dev'...
[22:28:34] set-env ENV => development
[22:28:34] Finished '_set-env:dev' after 7.63 ms
[22:28:34] Starting 'watch'...

最佳答案

您可能在gulpfile的顶部附近有这样的内容：

var webpackConfig = require('./webpack.config.js');

这意味着您的Webpack配置将在_set-env:dev任务运行之前进行评估。请记住：您的gulpfile仅定义任务。直到评估完整个gulpfile后，任务本身才运行。

您需要通过在gulpfile顶部删除行并将_set-env:dev直接放入您的require()任务中，直到执行watch任务后才需要进行webpack配置：

gulp.task("watch", ["_set-env:dev"], function() {
    // modify default webpack configuration for Development Server
    var webpackDevConfig = Object.create(require('./webpack.config.js'));

关于node.js - 如何将Gulp的process.env.NODE_ENV传递给Webpack？，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/39882186/