如何设置JavaScript对象的属性值？

Question

I have a JavaScript object that looks something like this:

obj = {
  person: {
    male: true,
    age: 10
  },
  state: {
    quit: false,
    rain: -3
  },
  game: {
     settings: {
       lang: 'en',
       os: 'win',
       ver: 10,
     },
  },
  next: 55,
  last: 10,
};

I'd like to create a function that can be used to set any of the obj's values like this:

function updateObj( property /*: string[]*/, value /*: any*/ ) {

  obj[property[0]][property[1]] = value;  <-- How to generalize? 

}

So then I can do things like:

updateObj( ['person', 'male'], false );
updateObj( ['state', 'rain'], 19 );

However the current implementation won't work properly if the property parameter length is not equal to 2. How can this line of code:

  obj[property[0]][property[1]] = value;

be generalized to work with any array size of property?

Answer 1

Below method will achieve your result, used reduceRight below

// with reduceRight
function updateObj(prop, value) {
    prop  = prop.reverse()
    prop.reduceRight((o, d, i) => i == 0 ? (o[d] = value): o[d] , obj)
}

// with Reduce (efficient than above)
function updateObj(prop, value) {
    prop.reduce((o, d, i) => i == prop.length -1 ? (o[d] = value): o[d] , obj) 
}

updateObj( ['person', 'male'], false );
updateObj( ['state', 'rain'], 19 );

Answer 2

Iterate over the property parts and for each one get the nested object:

function updateObj( property /*: string[]*/, value /*: any*/ ) {
    var base = obj;
    for (var i = 0; i < property.length - 1; i++) {
        base = base[property[i]];
    }
    base[property[property.length - 1]] = value;
}

Answer 3

You could save the last key and reduce the object by taking the keys and return the last object reference. For not given properties assign an empty object.

At the end take the last key and assign the value.

 function updateObj(properties, value) { var last = properties.pop(); properties.reduce((o, k) => o[k] = o[k] || {}, obj)[last] = value; } var obj = { person: { male: true, age: 10 }, state: { quit: false, rain: -3 }, game: { settings: { lang: 'en', os: 'win', ver: 10 }, }, next: 55, last: 10 }; updateObj(['person', 'male'], false); updateObj(['state', 'rain'], 19); updateObj(['banana', 'ware'], 'snakeoil'); console.log(obj); 

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