26 lines
933 B
Markdown
26 lines
933 B
Markdown
---
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title: flattenObject
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tags: object,recursion,intermediate
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---
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Flatten an object with the paths for keys.
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Use recursion.
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Use `Object.keys(obj)` combined with `Array.prototype.reduce()` to convert every leaf node to a flattened path node.
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If the value of a key is an object, the function calls itself with the appropriate `prefix` to create the path using `Object.assign()`.
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Otherwise, it adds the appropriate prefixed key-value pair to the accumulator object.
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You should always omit the second argument, `prefix`, unless you want every key to have a prefix.
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```js
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const flattenObject = (obj, prefix = '') =>
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Object.keys(obj).reduce((acc, k) => {
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const pre = prefix.length ? prefix + '.' : '';
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if (typeof obj[k] === 'object') Object.assign(acc, flattenObject(obj[k], pre + k));
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else acc[pre + k] = obj[k];
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return acc;
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}, {});
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```
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```js
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flattenObject({ a: { b: { c: 1 } }, d: 1 }); // { 'a.b.c': 1, d: 1 }
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``` |