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isNaN(num) // returns true if the variable does NOT contain a valid number
isNaN(123) // false
isNaN('123') // false
isNaN('1e10000') // false (This translates to Infinity, which is a number)
isNaN('foo') // true
isNaN('10px') // true
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// native returns true if the variable does NOT contain a valid number
isNaN(num)
// can be wrapped for making simple and readable
function isNumeric(num){
return !isNaN(num)
}
isNumeric(123) // true
isNumeric('123') // true
isNumeric('1e10000') // true (This translates to Infinity, which is a number)
isNumeric('foo') // false
isNumeric('10px') // false
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function isNumeric(num) {
if (num === '' || num === null) {
return false
}
return !isNaN(num)
}
isNumeric('') //false
isNumeric('7') //true
isNumeric(7) //true
isNumeric('7a') //false
isNumeric('a') //false
isNumeric(null) //false
isNumeric(0) //true
isNumeric('0') //true
isNumeric(true) //true
isNumeric(false) //true
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function isInt(str) {
return !isNaN(str) && Number.isInteger(parseFloat(str));
}
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const str = "vikash123!";
const hasNumber = /\d/.test(str);
console.log(hasNumber) // true
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function isNumeric(num){
return !isNaN(num)
}
isNumeric("23.33"); //true, checking if string is a number.
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function isNumber(value) {
return !isNaN(value) && parseFloat(Number(value)) === value && !isNaN(parseInt(value, 10));
}
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function isNumeric(str) {
if (typeof str != "string") return false // we only process strings!
return !isNaN(str) && // use type coercion to parse the _entirety_ of the string (`parseFloat` alone does not do this)...
!isNaN(parseFloat(str)) // ...and ensure strings of whitespace fail
}