Question

How to check if string is a negative integer in Node.js

Answer 1

function isNegativeInteger(s) {
    if (typeof s !== 'string') {
        return false;
    }
 
    const n = Number(s);
 
    if (Number.isInteger(n) && n < 0) {
        return true;
    }
 
    return false;
}
 
 
 
console.log(isNegativeInteger('0')); 
console.log(isNegativeInteger('2')); 
console.log(isNegativeInteger('-9')); 
console.log(isNegativeInteger('-3.14')); 
console.log(isNegativeInteger('')); 
console.log(isNegativeInteger('node.js')); 
console.log(isNegativeInteger(' ')); 
 
 

 
 
/*
run:
 
false
false
true
false
false
false
false
 
*/

 

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