65 lines
1.5 KiB
Markdown
65 lines
1.5 KiB
Markdown
---
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title: walkThrough
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tags: object,recursion,generator,advanced
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firstSeen: 2020-12-31T13:03:15+02:00
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lastUpdated: 2020-12-31T13:03:15+02:00
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---
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Creates a generator, that walks through all the keys of a given object.
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- Use recursion.
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- Define a generator function, `walk`, that takes an object and an array of keys.
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- Use a `for...of` loop and `Object.keys()` to iterate over the keys of the object.
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- Use `typeof` to check if each value in the given object is itself an object.
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- If so, use the `yield*` expression to recursively delegate to the same generator function, `walk`, appending the current `key` to the array of keys. Otherwise, `yield` the an array of keys representing the current path and the value of the given `key`.
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- Use the `yield*` expression to delegate to the `walk` generator function.
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```js
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const walkThrough = function* (obj) {
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const walk = function* (x, previous = []) {
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for (let key of Object.keys(x)) {
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if (typeof x[key] === 'object') yield* walk(x[key], [...previous, key]);
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else yield [[...previous, key], x[key]];
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}
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};
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yield* walk(obj);
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};
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```
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```js
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const obj = {
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a: 10,
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b: 20,
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c: {
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d: 10,
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e: 20,
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f: [30, 40]
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},
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g: [
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{
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h: 10,
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i: 20
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},
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{
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j: 30
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},
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40
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]
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};
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[...walkThrough(obj)];
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/*
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[
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[['a'], 10],
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[['b'], 20],
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[['c', 'd'], 10],
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[['c', 'e'], 20],
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[['c', 'f', '0'], 30],
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[['c', 'f', '1'], 40],
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[['g', '0', 'h'], 10],
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[['g', '0', 'i'], 20],
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[['g', '1', 'j'], 30],
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[['g', '2'], 40]
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]
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*/
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```
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