2017-04-26T05:06:50Z||2017-09-21T07:04:50Z


详细信息是:

iterators/generators require regenerator-runtime, which is too heavyweight for this guide to allow them. Separately, loops should be avoided in favor of array iterations. (no-restricted-syntax)

基本上就是不推荐用for-in for-of。推荐用.forEach,感觉有点变态的化,可以禁用这个rule,改写.eslintrc.js,增加:

{
  rules: {
    "no-restricted-syntax": 0,
  },
};

Airbnb的JavaScript Style上有说明(https://github.com/airbnb/javascript#iterators--nope ),原文是:

Iterators and Generators

<a name="iterators--nope"></a><a name="11.1"></a>

  • 11.1 Don't use iterators. Prefer JavaScript's higher-order functions instead of loops like for-in or for-of. eslint: no-iterator no-restricted-syntax

    Why? This enforces our immutable rule. Dealing with pure functions that return values is easier to reason about than side effects.

    Use map() / every() / filter() / find() / findIndex() / reduce() / some() / ... to iterate over arrays, and Object.keys() / Object.values() / Object.entries() to produce arrays so you can iterate over objects.

    const numbers = [1, 2, 3, 4, 5];
    
    // bad
    let sum = 0;
    for (let num of numbers) {
      sum += num;
    }
    sum === 15;
    
    // good
    let sum = 0;
    numbers.forEach(num => sum += num);
    sum === 15;
    
    // best (use the functional force)
    const sum = numbers.reduce((total, num) => total + num, 0);
    sum === 15;
    
    // bad
    const increasedByOne = [];
    for (let i = 0; i < numbers.length; i++) {
      increasedByOne.push(numbers[i] + 1);
    }
    
    // good
    const increasedByOne = [];
    numbers.forEach(num => increasedByOne.push(num + 1));
    
    // best (keeping it functional)
    const increasedByOne = numbers.map(num => num + 1);
    

<a name="generators--nope"></a><a name="11.2"></a>

  • 11.2 Don't use generators for now.

    Why? They don't transpile well to ES5.

<a name="generators--spacing"></a>

  • 11.3 If you must use generators, or if you disregard our advice, make sure their function signature is spaced properly. eslint: generator-star-spacing

    Why? function and * are part of the same conceptual keyword - * is not a modifier for function, function* is a unique construct, different from function.

    // bad
    function * foo() {
      // ...
    }
    
    // bad
    const bar = function * () {
      // ...
    };
    
    // bad
    const baz = function *() {
      // ...
    };
    
    // bad
    const quux = function*() {
      // ...
    };
    
    // bad
    function*foo() {
      // ...
    }
    
    // bad
    function *foo() {
      // ...
    }
    
    // very bad
    function
    *
    foo() {
      // ...
    }
    
    // very bad
    const wat = function
    *
    () {
      // ...
    };
    
    // good
    function* foo() {
      // ...
    }
    
    // good
    const foo = function* () {
      // ...
    };