> For the complete documentation index, see [llms.txt](https://lochiwei.gitbook.io/web/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://lochiwei.gitbook.io/web/js/iteration/generator/examples/interleave.md).

# \*interleave()

interleaves the values of a list of iterables

[JS](/web/js.md) ⟩ [objects](/web/js/val/obj.md) ⟩ [built-in](/web/js/val/builtin.md) ⟩ [Generator](/web/js/iteration/generator.md) ⟩ [generator function](/web/js/iteration/generator/func.md) ⟩ [compostion](/web/js/iteration/generator/func/compose.md) ⟩ \*interleave()

{% hint style="success" %} <mark style="color:purple;">**interleave**</mark> the values of <mark style="color:yellow;">**a list of**</mark> [iterable](/web/js/iteration/iterable.md)s into a <mark style="color:yellow;">**single**</mark> [generator function](/web/js/iteration/generator/func.md).
{% endhint %}

{% tabs %}
{% tab title="💾 程式" %}

* replit：[interleave(...iterables)](https://replit.com/@pegasusroe/interleaveiterables#interleave.js)

```javascript
// ⭐ interleave()
//  interleaves the values of a list of iterables
function* interleave(...iterables) {

    // iterables -> iterators
    let iterators = iterables.map(it => it[Symbol.iterator]());
    let i = 0;    // index of current iterator

    // while still some iterators
    while (iterators.length > 0) { 
        
        // if last iterator reached, go back to first
        if (i >= iterators.length) i = 0;

        // get next iteration result of current iterator
        let result = iterators[i].next();
        
        if (result.done) {             // if current iterator done,
            iterators.splice(i, 1);    //   • remove it.
        } else {                       // otherwise, 
            yield result.value;        //   • yield the value 
            i += 1;                    //   • go to next iterator.
        }
    }

    // all iterators done
    return;
}

// export
module.exports = interleave;
```

💈範例：

* require： [Iterator](/web/js/iteration/iterator/iterator.md), [\*integers()](/web/js/iteration/generator/examples/integers.md)

```javascript
// ⭐ import
const Iterator   = require('./Iterator.js');    // extend iterators
const integers   = require('./integers.js');    // integers()
const interleave = require('./interleave.js');  // interleave()
// --------------------------------------------------------------

//                           ⭐ values start taken from here
interleave(               //  ↓
    integers().take(5),   //  0 ,  1 , 2, 3, 4
    "ab",                 // 'a', 'b'
    [0]                   //  0
).toArray()
// [ 0, 'a', 0, 1, 'b', 2, 3, 4]
```

{% endtab %}

{% tab title="👥 相關" %}

* [\*zip()](/web/js/iteration/generator/examples/zip.md) is <mark style="color:yellow;">**similar**</mark> to but <mark style="color:red;">**different**</mark> from <mark style="color:purple;">**interleave()**</mark>.
* [\*sequence()](/web/js/iteration/generator/examples/seq.md) yields values <mark style="color:yellow;">**sequentially**</mark>.
  {% endtab %}

{% tab title="📗 參考" %}

* [ ] JavaScript: The Definitive Guide ⟩ 12.3 Generators
  {% endtab %}
  {% endtabs %}