How to Check if All Values are True in a JavaScript Array

How to Check if All Values are True in a JavaScript Array

Ferenc Almasi β€’ 2021 May 04 β€’ πŸ“– 1 min read

If you ever need to check if an array only has true values in JavaScript, you can use Array.every in combination of the global Boolean object:

const validations = [

const isEntirelyTrue = validations.every(Boolean);

// The above is equivalent to saying:
const isEntirelyTrue = validations.every(item => !!item);
const isEntirelyTrue = validations.every(item => item === true);
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The every method tests whether all elements in the array pass the test that is implemented in the callback function. It is exactly what we need for this purpose. It always returns a boolean value: either true or false.

Combining this with the global Boolean, which is a wrapper for boolean values, we can get the desired effect. It returns false if the value is one of:

[0, -0, null, false, NaN, undefined, '']
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Any other value will produce true. It is equivalent of double negating a value to cast it to a boolean value, or comparing it to the boolean true.

How to Check if All Values are True in a JavaScript Array
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