JavaScript: Truncate a string if it is longer than the specified number of characters

Last update on May 30 2022 10:01:15 (UTC/GMT +8 hours)

JavaScript String: Exercise-16 with Solution

Write a JavaScript function to truncate a string if it is longer than the specified number of characters. Truncated strings will end with a translatable ellipsis sequence ("…") (by default) or specified characters.

Test Data:
console.log(text_truncate('We are doing JS string exercises.'))
console.log(text_truncate('We are doing JS string exercises.',19))
console.log(text_truncate('We are doing JS string exercises.',15,'!!'))
"We are doing JS string exercises."
"We are doing JS ..."
"We are doing !!"

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS truncates a string</title>
</head>
<body>
</body>
</html>

JavaScript Code:

text_truncate = function(str, length, ending) {
    if (length == null) {
      length = 100;
    }
    if (ending == null) {
      ending = '...';
    }
    if (str.length > length) {
      return str.substring(0, length - ending.length) + ending;
    } else {
      return str;
    }
  };
console.log(text_truncate('We are doing JS string exercises.'))
console.log(text_truncate('We are doing JS string exercises.',19))
console.log(text_truncate('We are doing JS string exercises.',15,'!!'))

Sample Output:

We are doing JS string exercises.
We are doing JS ...
We are doing !!

Flowchart:

Live Demo:

See the Pen JavaScript Truncate a string if it is longer than the specified number of characters - string-ex-16 by w3resource (@w3resource) on CodePen.

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Previous: Write a JavaScript function to humanized number (Formats a number to a human-readable string.) with the correct suffix such as 1st, 2nd, 3rd or 4th.
Next: Write a JavaScript function to chop a string into chunks of a given length.

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