How to use replace function in js

The replace() function in JavaScript is used to find and replace the specified value in a string. The syntax is string.replace(searchValue, replaceValue), where searchValue is the value to be found, replaceValue is the replacement value, and the new string after replacement is returned. Optional regular expression flags can specify replacement behavior, such as global replacement (g), case-insensitive (i), or multi-line replacement (m).

Using the replace() function in JavaScript

Thereplace() function is used to find and replace strings the specified value. The syntax is as follows:

<code>string.replace(searchValue, replaceValue)</code>

where:

• string is the string to be searched and replaced.
• searchValue is the value to be found.
• replaceValue is the value to be replaced.

Usage:

replace() function returns a new string in which all substrings matching searchValue have been replaced by replaceValue. The original string is not modified.

Example:

<code>let str = "Hello, world!";
let newStr = str.replace("world", "JavaScript");
console.log(newStr); // 输出："Hello, JavaScript!"</code>

Options:

replace() function can also use optional regular expression flags ( flags) to specify the replacement behavior:

• g - Global replacement: Replace all matches.
• i - Case-insensitive: Ignore case for replacement.
• m - Multi-line replacement: Treat each line as a separate string for replacement.

Example:

<code>let str = "Hello, WORLD! Hello, world!";
let newStr = str.replace(/world/gi, "JavaScript");
console.log(newStr); // 输出："Hello, JavaScript! Hello, JavaScript!"</code>

In the above example, the regular expression /world/g matches all instances of the "world" string (size-insensitive Write).

Other Notes:

• If searchValue is not found in the string, the replace() function will return the original string.
• For searchValue that contains regular expression characters, you need to escape it or use the RegExp() constructor to create a regular expression object.
• For a searchValue of an empty string, the replace() function will replace everything in the string.

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