I am trying to remove a property from an object using the spread operator. Traditionally I have done this:
const original_object = { prop1 : 'string1', prop2: 'string2' };
const { prop1, ...rest } = original_object;
In the above situation, the removed property(prop1) will no longer exist within the rest object.
Suppose there is a more intricate property that I would like to remove, such as an object within the object.
const original_object = {
prop1: 'string1'
prop2: {
prop3: 'string3',
prop4: 'string4'
}
}
const { *remove prop3 of prop2 only here*, ...rest} = original_object;
console.log(prop3); // => 'string3';
What is the most elegant/easiest solution to do this? I want everything but the one prop3
of prop2
to be included in the object, in the exact same structure.
Do it in two steps - first destructure the prop3
out, then create a new object, combining the rest of the outer object with the prop2 with the prop3 removed from it:
const original_object = {
prop1: 'string1',
prop2: {
prop3: 'string3',
prop4: 'string4'
}
};
const { prop2: { prop3, ...restProp2 }, ...restOrig} = original_object;
const newObj = { ...restOrig, prop2: restProp2 };
console.log(prop3); // => 'string3';
console.log(newObj);
While you could do this in just one statement with a hack, I wouldn't recommend it.
If you find yourself doing this often with deeply nested properties, and don't like the extra line, maybe consider a helper function along the lines of:
const getNestedFrom = (obj, propStr) => {
// make a copy, don't mutate the original object
const newObj = JSON.parse(JSON.stringify(obj));
const props = propStr.split('.');
const lastProp = props.pop();
const lastObj = props.reduce((a, prop) => a[prop], newObj);
const val = lastObj[lastProp];
delete lastObj[lastProp];
return [newObj, val];
};
const original_object = {
prop1: 'string1',
prop2: {
prop3: 'string3',
prop4: 'string4'
}
};
const [newObj, prop3] = getNestedFrom(original_object, 'prop2.prop3');
console.log(prop3); // => 'string3';
console.log(newObj);
Just for curiosity's sake (please don't do this), the hack would be to use a default property which definitely won't exist:
const original_object = {
prop1: 'string1',
prop2: {
prop3: 'string3',
prop4: 'string4'
}
};
const [
{ prop2: { prop3, ...restProp2 }, ...restOrig},
newObj = { ...restOrig, prop2: restProp2 }
] = [original_object]
console.log(prop3); // => 'string3';
console.log(newObj);
But that would be significantly (and needlessly) confusing.
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