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Underscore.js _.isMap() Function

  • Last Updated : 25 Nov, 2021

Underscore.js is a library in javascript that makes operations on arrays, string, objects much easier and handy. _.isMap() function is used to check whether the given object is javascript Map or not.

Note: It is very necessary to link the underscore CDN before going and using underscore functions in the browser. When linking the underscore.js CDN The “_” is attached to the browser as a global variable.

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Syntax:

_.isMap(object);

Parameters : 



  • object : It is any javascript object such as array, string, maps, set etc.

Returns : It returns the boolean value. If the object is a Map of javascript it returns true otherwise false is returned by the function.

Few Examples are given below for a better understanding of the function.

Example 1:

When an array is given the output is false.




<!DOCTYPE html>
<html lang="en">
<head>
  <meta charMap="UTF-8">
  <meta name="viewport" 
        content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src=
  </script
</head>
<body>
  <script>
    //creating a array of size 2 using constructor
    var obj= new Array(2);
    //filling array with value 10
    obj.fill(10);
    //using the underscore.js function _.isMap()
    var isMap= _.isMap(obj);
    console.log(isMap)
    //If the given object is Map it prints the object is Map.
    if(isMap)
    console.log(`The ${obj} is the Map of Javascript.`)
    else
    console.log(`The ${obj} is not the Map of Javascript.`)
  </script>
</body>
</html>

Output:

Example 2:

When a Map is given it returns true.




<!DOCTYPE html>
<html lang="en">
<head>
  <meta charMap="UTF-8">
  <meta name="viewport" 
        content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src=
  </script
</head>
<body>
  <script>
    //creating a Map using constructor
    var obj= new Map();
    //using the underscore.js function _.isMap()
    var isMap= _.isMap(obj);
    console.log(isMap)
    //If the given object is Map it prints the object is Map.
    if(isMap)
    console.log(`The ${obj} is the Map of Javascript.`)
    else
    console.log(`The ${obj} is not the Map of Javascript.`)
  </script>
</body>
</html>

Output:

Example 3:

When giving an object as a parameter the output is false




<!DOCTYPE html>
<html lang="en">
<head>
  <meta charMap="UTF-8">
  <meta name="viewport" 
        content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src=
  </script
</head>
<body>
  <script>
    //creating a Javascript Object using constructor
    var obj= new Object();
    obj={
      "a":1,
      "b":2
    }
    //using the underscore.js function _.isMap()
    var isMap= _.isMap(obj);
    console.log(isMap)
    //If the given object is Map it prints the object is Map.
    if(isMap)
    console.log(`The ${obj} is the Map of Javascript.`)
    else
    console.log(`The ${obj} is not the Map of Javascript.`)
  </script>
</body>
</html>

Output:




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