Underscore.js is a JavaScript library that provides a lot of useful functions that help in the programming in a big way like the map, filter, invoke, etc. even without using any built-in objects.
The _.iteratee() function is an inbuilt function in Underscore which is used to generate a callback that can be applied to every element in a collection. This method supports multiple shorthand syntaxes for common callback use cases and returns the output depending on the type of the value.
Syntax:
_.iteratee( value, context )
Parameters: This method accepts two parameters as mentioned above and described below:
- value: It is the stated value.
- context: It is the context to be used. It is an optional parameter.
Return Value: This method returns the output depending on the type of value.
Example 1: In this example, no parameter is used with the method.
<!DOCTYPE html> <html>
<head>
<script src=
</script>
</head>
<body>
<script type="text/javascript">
// Calling iteratee method with
// no parameters
console.log(_.iteratee());
</script>
</body>
</html>
|
Output:
function(n){return n}Example 2: In this example, a user-defined function is given to the method.
<!DOCTYPE html> <html>
<head>
<script src=
</script>
</head>
<body>
<script type="text/javascript">
// Calling iteratee method
// with its parameter
console.log(
_.iteratee(
function (num) {
return num * 4;
}
)
);
</script>
</body>
</html>
|
Output:
function(num) { return num * 4; }Example 3: In this example, a key-value pair is passed as the parameter.
<!DOCTYPE html> <html>
<head>
<script src=
</script>
</head>
<body>
<script type="text/javascript">
// Calling iteratee method
// with its parameter
console.log(
_.iteratee(
{ portal: 'GeeksforGeeks' }, []
)
);
</script>
</body>
</html>
|
Output:
function(n){return h.isMatch(n,r)}
Example 4: In this example, a string is passed as the parameter.
<!DOCTYPE html> <html>
<head>
<script src=
</script>
</head>
<body>
<script>
// Calling iteratee method with
// its parameter
console.log(
_.iteratee('GfG', [])
);
</script>
</body>
</html>
|
Output:
function(n){return null==n?void 0:n[r]}