Question 237108 in Javascript Question posted in
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Any shorter and computationally faster expression of checking if x in Array || y in Array || z in Object keys in Javascript

I want to check if x, y or z(all string) exists in the Object keys, my longer expression:

if (x in demoObject || y in demoObject || z in demoObject){
 // do the following action
}

Is there a shorter and computationally faster way to do it(if can’t achieve both of them at the same code, I want the solution for each side), if I need to check more than 10 values whether they exist in the object keys?

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2

Answers


  1. 0

    You could take the prototype function Object.hasOwnProperty and handover the object as thisArg.

    const
    demoObject = { 3: 'hello', 5: 'world' },
    look_for_these = [ 1, 4, 5 ],
    has_key = look_for_these.some(Object.prototype.hasOwnProperty, demoObject);

console.log(has_key);
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  2. 0 
    [x, y, z].every(key => typeof demoObject[key] !== 'undefined')

    or in your example

    [x, y, z].every(key => key in demoObject)
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