Created
October 8, 2021 20:58
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function isObjNotArray(obj) { | |
return obj && typeof obj == 'object' && !Array.isArray(obj) | |
} | |
function isIterable(obj) { | |
let type = false | |
if (isObjNotArray(obj)) type = 'obj' | |
else if (Array.isArray(obj)) type = 'arr' | |
return type | |
} | |
function mergeDeep(source, target) { | |
if (source === undefined) return target | |
if (target === undefined) return source | |
let allProps = [], | |
sourceProps, targetProps, sourceType, targetType, type, merged, iterable, filler | |
sourceType = isIterable(source) | |
targetType = isIterable(target) | |
type = sourceType | |
if (source && target && sourceType != targetType) { | |
throw 'source, target type mismatch' | |
} | |
if (sourceType == 'obj') { | |
sourceProps = Object.keys(source) | |
} else if (sourceType == 'arr') { | |
sourceProps = source | |
} else { | |
return source | |
} | |
if (targetType == 'obj') { | |
targetProps = Object.keys(target) | |
} else if (targetType = 'arr') { | |
targetProps = target; | |
} else { | |
throw 'mergeDeep target must be an Object or Array' | |
} | |
sourceProps.forEach(prop => { | |
allProps.push(prop); | |
}) | |
targetProps.forEach(prop => { | |
allProps.push(prop); | |
}) | |
allProps = [...new Set(allProps)] | |
if (type == 'obj') { | |
merged = {} | |
} else if (type == 'arr') { | |
merged = [] | |
} | |
allProps.forEach(prop => { | |
if (type == 'obj') { | |
if (source[prop]) { | |
if (isIterable(source[prop])) { | |
if (isIterable(target[prop])) { | |
merged[prop] = mergeDeep(source[prop], target[prop]) | |
} else { | |
merged[prop] = source[prop] | |
} | |
} else { | |
merged[prop] = source[prop] | |
} | |
} else { | |
if (source[prop] !== undefined) { | |
merged[prop] = source[prop] | |
} else { | |
merged[prop] = target[prop] | |
} | |
} | |
} else { | |
iterable = isIterable(prop) | |
if (iterable) { | |
if (iterable == 'obj') { | |
filler = {} | |
} else if (iterable == 'arr') { | |
filler = [] | |
} | |
merged.push(mergeDeep(prop, filler)) | |
} else { | |
merged.push(prop) | |
} | |
} | |
}) | |
return merged | |
} | |
const parent1 = { | |
visualTraits: { | |
color: 'black', | |
size: 'large' | |
}, | |
personalityTraits: { | |
friendliness: 5 | |
} | |
} | |
const parent2 = { | |
personalityTraits: { | |
friendliness: 4 | |
} | |
} | |
const parent3 = { | |
visualTraits: { | |
color: 'brown', | |
size: 'medium' | |
}, | |
personalityTraits: { | |
friendliness: 5 | |
} | |
} | |
const parent4 = { | |
personalityTraits: { | |
friendliness: 4 | |
}, | |
visualTraits: { | |
size: 'small' | |
} | |
} | |
const child1 = mergeDeep(parent1, parent2) | |
const child2 = mergeDeep(parent3, parent4) | |
const grandchild = mergeDeep(child1, child2) | |
console.log('child1', child1) | |
console.log('child2', child2) | |
console.log('grandchild', grandchild) | |
// I want any propoerties to be references to their original | |
// ancestor object merged from | |
// so that if I change: | |
parent1.visualTraits.color = "pink" | |
// grandchild with that inherited "black" color property | |
// passed (desireably but not in this case) by reference | |
// to the original parent1 will also see this change. Howver: | |
console.log('grandchild.visualTraits.color', grandchild.visualTraits.color) // black |
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