javascript - 类型错误 [ERR_INVALID_CALLBACK] : Callback must be a function

Question

我想制作一个脚本来向 angular webpack 应用程序添加新规则，如下所示。有时代码会部分执行，有时会出错。

const fs = require('fs');
const commonCliConfig = 'node_modules/@angular-devkit/build-angular/src/angular-cli-files/models/webpack-configs/common.js';
const pug_rule = "\n{ test: /\\.pug$/, loader: ['raw-loader' , 'pug-html-loader' ]},";
var configText = "";
fs.readFile(commonCliConfig, function(err, data) {
    if (err) throw err;
    configText = data.toString();
    if (configText.indexOf(pug_rule) > -1) { return; }
    const position = configText.indexOf('rules: [') + 8;
    const output = [configText.slice(0, position), pug_rule, configText.slice(position)].join('');
    const file = fs.openSync(commonCliConfig, 'r+');
    fs.writeFile(file, output);
    fs.close(file);
});


Terminal node pug-rule.js
fs.js:148
    throw new ERR_INVALID_CALLBACK();
    ^

TypeError [ERR_INVALID_CALLBACK]: Callback must be a function
    at makeCallback (fs.js:148:11)
    at Object.fs.close (fs.js:520:20)
    at path/pug-rule.js:18:5
    at FSReqWrap.readFileAfterClose [as oncomplete] (fs.js:422:3)

Answer 1

fs.writeFile(...) 需要第三个(或第四个)参数，它是在操作完成时调用的回调函数。您应该提供回调函数或使用 fs.writeFileSync(...)

参见 node fs docs了解更多信息。