To check if a variable is a string in JavaScript, you can use the typeof
operator and the Object.prototype.toString.call
method.
Here are some examples of how to use these methods to check if a variable is a string:
1. To check if a variable is a string using the typeof
operator, you can use the following code:
function isString(val) {
return typeof val === 'string';
}
console.log(isString('hello')); // Outputs: true
console.log(isString(123)); // Outputs: false
This function returns true
if the type of the val
argument is 'string'
, and false
otherwise.
2. To check if a variable is a string using the Object.prototype.toString.call
method, you can use the following code:
function isString(val) {
return Object.prototype.toString.call(val) === '[object String]';
}
console.log(isString('hello')); // Outputs: true
console.log(isString(123)); // Outputs: false
This function returns true
if the Object.prototype.toString
method applied to the val
argument returns the string '[object String]'
, and false
otherwise.
Both of these methods can be used to check if a variable is a string in JavaScript. The typeof
operator is simpler and faster, but it may not always return the expected results for certain types of values, such as objects or arrays that have been converted to strings. The Object.prototype.toString.call
method is more reliable, but it is slightly slower and more verbose.