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Node.js buffer indexOf() Method

❮ Buffer Module


Example

Check if a buffer incudes the phrase "welcome", and return the position:

var buf = Buffer.from('Hello, and welcome to Rome!');

console.log(buf.indexOf('welcome'));
Run example »

Definition and Usage

The indexOf() method checks if a specified value is present in the buffer and returns the position.

This method returns -1 if the value to search for never occurs.

If the specified value occurs more than once, only the position of the first occurrence will be returned.

See also: the lastIndexOf() method, which returns the last occurrence of the specified value.


Syntax

buffer.indexOf(value, start, encoding);

Parameter Values

Parameter Description
value Required. What to search for. Legal value types:
String
Buffer
Number (Integer)
start Optional. Where to begin the search. Default 0
encoding Optional. If the value is a string, this parameter is used to specify its encoding. Default "utf8"

Technical Details

Return Value: A Number, representing the position where the specified search value occurs for the first time, or -1 if it never occurs
Node.js Version: 1.5.0

More Examples

Example

Return the first occurrence of the letter "e":

var buf = Buffer.from('Hello, and welcome to Rome!');

console.log(buf.indexOf('e'));
Run example »

❮ Buffer Module