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30secondsofcode
2018-03-06 18:59:57 +00:00
parent 883063e278
commit e7c5bcf6c6
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17
README.md
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@ -2866,22 +2866,19 @@ zipObject(['a', 'b'], [1, 2, 3]); // {a: 1, b: 2}
Creates an array of elements, grouped based on the position in the original arrays and using function as the last value to specify how grouped values should be combined.
Check if the last argument provided in a function.
Check if the last argument provided is a function.
Use `Math.max()` to get the longest array in the arguments.
Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements.
If lengths of the argument-arrays vary, `undefined` is used where no value could be found.
The function is invoked with the elements of each group `(...group)`.
```js
const zipWith = (...arrays) => {
const length = arrays.length;
let fn = length > 1 ? arrays[length - 1] : undefined;
fn = typeof fn == 'function' ? (arrays.pop(), fn) : undefined;
const maxLength = Math.max(...arrays.map(x => x.length));
const result = Array.from({ length: maxLength }).map((_, i) => {
return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]);
});
return fn ? result.map(arr => fn(...arr)) : result;
const zipWith = (...array) => {
const fn = typeof array[array.length - 1] === 'function' ? array.pop() : undefined;
return Array.from(
{ length: Math.max(...array.map(a => a.length)) },
(_, i) => (fn ? fn(...array.map(a => a[i])) : array.map(a => a[i]))
);
};
```

15
docs/index.html
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@ -575,15 +575,12 @@ Object<span class="token punctuation">.</span><span class="token function">assig
props<span class="token punctuation">.</span><span class="token function">reduce</span><span class="token punctuation">((</span>obj<span class="token punctuation">,</span> prop<span class="token punctuation">,</span> index<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">((</span>obj<span class="token punctuation">[</span>prop<span class="token punctuation">]</span> <span class="token operator">=</span> values<span class="token punctuation">[</span>index<span class="token punctuation">]),</span> obj<span class="token punctuation">), {});</span>
</pre><label class="collapse">Show examples</label><pre class="language-js"><span class="token function">zipObject</span><span class="token punctuation">([</span><span class="token string">'a'</span><span class="token punctuation">,</span> <span class="token string">'b'</span><span class="token punctuation">,</span> <span class="token string">'c'</span><span class="token punctuation">], [</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">]);</span> <span class="token comment">// {a: 1, b: 2, c: undefined}</span>
<span class="token function">zipObject</span><span class="token punctuation">([</span><span class="token string">'a'</span><span class="token punctuation">,</span> <span class="token string">'b'</span><span class="token punctuation">], [</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">3</span><span class="token punctuation">]);</span> <span class="token comment">// {a: 1, b: 2}</span>
</pre><button class="primary clipboard-copy">&#128203;&nbsp;Copy to clipboard</button></div></div><div class="card fluid"><h3 id="zipwith" class="section double-padded">zipWith<mark class="tag">advanced</mark></h3><div class="section double-padded"><p>Creates an array of elements, grouped based on the position in the original arrays and using function as the last value to specify how grouped values should be combined.</p><p>Check if the last argument provided in a function. Use <code>Math.max()</code> to get the longest array in the arguments. Creates an array with that length as return value and use <code>Array.from()</code> with a map-function to create an array of grouped elements. If lengths of the argument-arrays vary, <code>undefined</code> is used where no value could be found. The function is invoked with the elements of each group <code>(...group)</code>.</p><pre class="language-js"><span class="token keyword">const</span> <span class="token function-variable function">zipWith</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token operator">...</span>arrays<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span>
<span class="token keyword">const</span> length <span class="token operator">=</span> arrays<span class="token punctuation">.</span>length<span class="token punctuation">;</span>
<span class="token keyword">let</span> fn <span class="token operator">=</span> length <span class="token operator">></span> <span class="token number">1</span> <span class="token operator">?</span> arrays<span class="token punctuation">[</span>length <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">] :</span> undefined<span class="token punctuation">;</span>
fn <span class="token operator">=</span> <span class="token keyword">typeof</span> fn <span class="token operator">==</span> <span class="token string">'function'</span> <span class="token operator">?</span> <span class="token punctuation">(</span>arrays<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">(),</span> fn<span class="token punctuation">) :</span> undefined<span class="token punctuation">;</span>
<span class="token keyword">const</span> maxLength <span class="token operator">=</span> Math<span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span><span class="token operator">...</span>arrays<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>x <span class="token operator">=></span> x<span class="token punctuation">.</span>length<span class="token punctuation">));</span>
<span class="token keyword">const</span> result <span class="token operator">=</span> Array<span class="token punctuation">.</span><span class="token keyword">from</span><span class="token punctuation">({</span> length<span class="token punctuation">:</span> maxLength <span class="token punctuation">}).</span><span class="token function">map</span><span class="token punctuation">((</span>_<span class="token punctuation">,</span> i<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span>
<span class="token keyword">return</span> Array<span class="token punctuation">.</span><span class="token keyword">from</span><span class="token punctuation">({</span> length<span class="token punctuation">:</span> arrays<span class="token punctuation">.</span>length <span class="token punctuation">}, (</span>_<span class="token punctuation">,</span> k<span class="token punctuation">)</span> <span class="token operator">=></span> arrays<span class="token punctuation">[</span>k<span class="token punctuation">][</span>i<span class="token punctuation">]);
});</span>
<span class="token keyword">return</span> fn <span class="token operator">?</span> result<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>arr <span class="token operator">=></span> <span class="token function">fn</span><span class="token punctuation">(</span><span class="token operator">...</span>arr<span class="token punctuation">)) :</span> result<span class="token punctuation">;
</pre><button class="primary clipboard-copy">&#128203;&nbsp;Copy to clipboard</button></div></div><div class="card fluid"><h3 id="zipwith" class="section double-padded">zipWith<mark class="tag">advanced</mark></h3><div class="section double-padded"><p>Creates an array of elements, grouped based on the position in the original arrays and using function as the last value to specify how grouped values should be combined.</p><p>Check if the last argument provided is a function. Use <code>Math.max()</code> to get the longest array in the arguments. Creates an array with that length as return value and use <code>Array.from()</code> with a map-function to create an array of grouped elements. If lengths of the argument-arrays vary, <code>undefined</code> is used where no value could be found. The function is invoked with the elements of each group <code>(...group)</code>.</p><pre class="language-js"><span class="token keyword">const</span> <span class="token function-variable function">zipWith</span> <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token operator">...</span>array<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">{</span>
<span class="token keyword">const</span> fn <span class="token operator">=</span> <span class="token keyword">typeof</span> array<span class="token punctuation">[</span>array<span class="token punctuation">.</span>length <span class="token operator">-</span> <span class="token number">1</span><span class="token punctuation">]</span> <span class="token operator">===</span> <span class="token string">'function'</span> <span class="token operator">?</span> array<span class="token punctuation">.</span><span class="token function">pop</span><span class="token punctuation">() :</span> undefined<span class="token punctuation">;</span>
<span class="token keyword">return</span> Array<span class="token punctuation">.</span><span class="token keyword">from</span><span class="token punctuation">(
{</span> length<span class="token punctuation">:</span> Math<span class="token punctuation">.</span><span class="token function">max</span><span class="token punctuation">(</span><span class="token operator">...</span>array<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>a <span class="token operator">=></span> a<span class="token punctuation">.</span>length<span class="token punctuation">)) },
(</span>_<span class="token punctuation">,</span> i<span class="token punctuation">)</span> <span class="token operator">=></span> <span class="token punctuation">(</span>fn <span class="token operator">?</span> <span class="token function">fn</span><span class="token punctuation">(</span><span class="token operator">...</span>array<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>a <span class="token operator">=></span> a<span class="token punctuation">[</span>i<span class="token punctuation">])) :</span> array<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span>a <span class="token operator">=></span> a<span class="token punctuation">[</span>i<span class="token punctuation">]))
);
};</span>
</pre><label class="collapse">Show examples</label><pre class="language-js"><span class="token function">zipWith</span><span class="token punctuation">([</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">], [</span><span class="token number">10</span><span class="token punctuation">,</span> <span class="token number">20</span><span class="token punctuation">], [</span><span class="token number">100</span><span class="token punctuation">,</span> <span class="token number">200</span><span class="token punctuation">], (</span>a<span class="token punctuation">,</span> b<span class="token punctuation">,</span> c<span class="token punctuation">)</span> <span class="token operator">=></span> a <span class="token operator">+</span> b <span class="token operator">+</span> c<span class="token punctuation">);</span> <span class="token comment">// [111,222]</span>
<span class="token function">zipWith</span><span class="token punctuation">(

9
snippets/zipWith.md
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@ -11,11 +11,10 @@ The function is invoked with the elements of each group `(...group)`.
```js
const zipWith = (...array) => {
const fn = typeof array[array.length - 1] === 'function' ? array.pop() : undefined;
return Array
.from(
{ length: Math.max(...array.map(a => a.length)) },
(_, i) => (fn ? fn(...array.map(a => a[i])) : array.map(a => a[i])),
);
return Array.from(
{ length: Math.max(...array.map(a => a.length)) },
(_, i) => (fn ? fn(...array.map(a => a[i])) : array.map(a => a[i]))
);
};
```