wp_json_encode() WP 4.1.0

Encode a variable into JSON, with some sanity checks. Checks strings and translates them to UTF-8.

The passed variable can be any type of data: array, string, object, number, etc.

Works based on PHP function json_encode().

No Hooks.

Return

String/false. The JSON encoded string, or false if it cannot be encoded.

Usage

wp_json_encode( $data, $options, $depth );

$data(mixed) (required)

Variable (usually an array or object) to encode as JSON.

$options(int)

Options to be passed to json_encode().

Constatnt that can be combined with | (bit mask): JSON_HEX_QUOT, JSON_HEX_TAG, JSON_HEX_AMP, JSON_HEX_APOS, JSON_NUMERIC_CHECK, JSON_PRETTY_PRINT, JSON_UNESCAPED_SLASHES, JSON_FORCE_OBJECT, JSON_PRESERVE_ZERO_FRACTION, JSON_UNESCAPED_UNICODE, JSON_PARTIAL_OUTPUT_ON_ERROR. The value of each constant is explained on the JSON constants page.

Default: 0

$depth(int)

Maximum depth to walk through $data. Must be greater than 0.
Default: 512

Examples

#1 Demonstration of work

wp_json_encode( 'one' ); // "one"

wp_json_encode( 2 ); // 2

wp_json_encode( array( 1, 'two' ) ); // [1,"two"]

wp_json_encode( (object) array( 1, 'two' ) ); // {"0":1,"1":"two"}

Code of wp json encode: wp-includes/functions.php ^{WP 5.2.2}

<?php
function wp_json_encode( $data, $options = 0, $depth = 512 ) {
	/*
	 * json_encode() has had extra params added over the years.
	 * $options was added in 5.3, and $depth in 5.5.
	 * We need to make sure we call it with the correct arguments.
	 */
	if ( version_compare( PHP_VERSION, '5.5', '>=' ) ) {
		$args = array( $data, $options, $depth );
	} elseif ( version_compare( PHP_VERSION, '5.3', '>=' ) ) {
		$args = array( $data, $options );
	} else {
		$args = array( $data );
	}

	// Prepare the data for JSON serialization.
	$args[0] = _wp_json_prepare_data( $data );

	$json = @call_user_func_array( 'json_encode', $args );

	// If json_encode() was successful, no need to do more sanity checking.
	// ... unless we're in an old version of PHP, and json_encode() returned
	// a string containing 'null'. Then we need to do more sanity checking.
	if ( false !== $json && ( version_compare( PHP_VERSION, '5.5', '>=' ) || false === strpos( $json, 'null' ) ) ) {
		return $json;
	}

	try {
		$args[0] = _wp_json_sanity_check( $data, $depth );
	} catch ( Exception $e ) {
		return false;
	}

	return call_user_func_array( 'json_encode', $args );
}

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