Created
December 2, 2015 13:06
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// ensure the keys being passed is an array of key paths | |
// example: 'a.b' becomes ['a', 'b'] unless it was already ['a', 'b'] | |
const keys = ks => Array.isArray(ks) ? ks : ks.split('.') | |
// traverse the set of keys left to right, | |
// returning the current value in each iteration. | |
// if at any point the value for the current key does not exist, | |
// return the default value | |
const deepGet = (o, kp, d) => keys(kp).reduce((o, k) => o && o[k] || d, o) | |
// traverse the set of keys right to left, | |
// returning a new object containing both properties from the object | |
// we were originally passed and our new property. | |
// | |
// Example: | |
// If o = { a: { b: { c: 1 } } } | |
// | |
// deepSet(o, ['a', 'b', 'c'], 2) will progress thus: | |
// 1. c = Object.assign({}, {c: 1}, { c: 2 }) | |
// 2. b = Object.assign({}, { b: { c: 1 } }, { b: c }) | |
// 3. returned = Object.assign({}, { a: { b: { c: 1 } } }, { a: b }) | |
const deepSet = (o, kp, v) => | |
keys(kp).reduceRight((v, k, i, ks) => | |
Object.assign({}, deepGet(o, ks.slice(0, i)), { [k]: v }), v) |
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