JavaScript: Test whether a string starts with a specified string

Last update on May 30 2022 10:01:47 (UTC/GMT +8 hours)

JavaScript String: Exercise-46 with Solution

Write a JavaScript function to test whether a string starts with a specified string.

Test Data:
console.log(startsWith('js string exercises', 'js'));
true

Pictorial Presentation:

JavaScript: Test whether a string starts with a specified string

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to test whether a string starts with a specified string</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function startsWith(input, string) {
  return input.indexOf(string) === 0;
}
console.log(startsWith('js string exercises', 'js'));

Sample Output:

true

Flowchart:

Live Demo:

See the Pen JavaScript Test whether a string starts with a specified string-string-ex-46 by w3resource (@w3resource) on CodePen.

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Previous: Write a JavaScript function to get humanized number with the correct suffix such as 1st, 2nd, 3rd or 4th.
Next: Write a JavaScript function to test whether a string ends with a specified string.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join());
arr.splice(2, 0, "Lene");
console.log(arr.join());

Ref: https://bit.ly/2BXbp04