JavaScript set all nested object properties to null

Question

How can I loop though each of this objects nested properties and set them all to null? I only need to go 2 levels deep so any props that are objects need to be null also.

var objs = {
    a: {
        prop1: {id: null, ctx: CanvasRenderingContext2D},
        prop2: true,
        prop3: null,
        prop4: null,
        prop5: true,
        prop6: null,
        prop7: null,
        prop8: true,
        prop9: null,
        prop10: null,
        prop11: true,
    },
    b: {
        prop1: {id: null, ctx: CanvasRenderingContext2D},
        prop2: true,
        prop3: null,
        prop4: null,
        prop5: true,
        prop6: null,
        prop7: null,
        prop8: true,
    },
    c: {
        prop1: {id: null, ctx: CanvasRenderingContext2D},
        prop2: true,
        prop3: null,
        prop4: null,
        prop5: true,
    }
}

I have tried this but it's going into the prop1 object which I don't want it to.

function nullify  (obj) { 
    for(key in obj) { 
        if (typeof obj[key] == "object") {
          obj[key] = nullify(obj[key]);
        }
        else if(obj[key] != null) {
            obj[key] = null;
        }
   }
   return obj;
}

nullify  (objs)

I haver also tried this but this goes through each letter of the outer key not the inner properties

for (obj in objs) {
    if (objs.hasOwnProperty(obj)) {
        for (key in obj) {
            if (obj.hasOwnProperty(key)) {
                obj[key] = null;
            }
        }
    }
}

The data structure screams to be an array instead of nested objects. Then you can just loop with very basic syntax. — Shilly
– Shilly, Commented Nov 20, 2018 at 16:09

Mark · Accepted Answer · 2018-11-20 16:13:03Z

5

Since you only need to go two levels, you can just loop over the keys of the child objects:

var objs = {a: {prop1: {id: null, ctx: `CanvasRenderingContext2D`},prop2: true,prop3: null,prop4: null,prop5: true,prop6: null,prop7: null,prop8: true,prop9: null,prop10: null,prop11: true,},b: {prop1: {id: null, ctx: `CanvasRenderingContext2D`},prop2: true,prop3: null,prop4: null,prop5: true,prop6: null,prop7: null,prop8: true,},c: {prop1: {id: null, ctx: `CanvasRenderingContext2D`},prop2: true,prop3: null,prop4: null,prop5: true,}}

Object.values(objs).forEach(val => {
  for (key in val) val[key] = null
})
console.log(objs)

answered Nov 20, 2018 at 16:13

Mark

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Comments

dipea · Accepted Answer · 2018-11-20 16:17:22Z

0

Does this do the trick?

function nullify(obj, depth) {
    depth = depth || 0;
    if (depth > 1) return obj;
    for(key in obj) {
        if (typeof obj[key] == "object") {
          obj[key] = nullify(obj[key], depth + 1);
        }
        else if(obj[key] != null) {
            obj[key] = null;
        }
   }
   return obj;
}

Edit:

Call it without passing in a depth argument: nullify(objs)

edited Nov 20, 2018 at 16:17

answered Nov 20, 2018 at 16:10

dipea

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1 Comment

fractal5 Over a year ago

It doesn't nullify the values inside at the second level namely ctx

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