2021-04-27
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#vanilla javascript
Felix Gerschau
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Apr 27, 2021 â‹… 7 min read

JavaScript iterators and generators: A complete guide

Felix Gerschau Felix is a frontend developer at Fitogram in Cologne, Germany.

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5 Replies to "JavaScript iterators and generators: A complete guide"

  1. Nice article. I was a little confused by the output shown for the `throw` example, so I tried running a modified version it in the browser.

    “`
    function* errorGenerator() {
    try {
    yield ‘one’;
    yield ‘two’;
    } catch(e) {
    console.error(e);
    }
    yield ‘three’;
    yield ‘four’;
    }

    const errorIterator = errorGenerator();

    console.log(errorIterator.next()); // outputs “{ value: ‘one’, done: false }”
    console.log(errorIterator.throw(‘Bam!’)); // outputs “Bam!” AND “{ value: ‘three’, done: false }”
    console.log(errorIterator.next()); // outputs “{ value: ‘four’, done: false }”
    console.log(errorIterator.next()); // outputs “{ value: undefined, done: true }”
    “`

    It appears that the throw doesn’t actually end the generator, but rather simulate an exception thrown, which is caught by the catch block, then continues the rest of the function normally.

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