How to create a function from a string in JavaScript ?
The task is to create a function from the string given in the format of the function. Here are a few techniques discussed with the help of JavaScript. Approach 1:
- Use the Function() Constructor to create a function from the string.
- It accepts any number of arguments(in form of string. The last one should be the body of the function.
- In this example, Only the body of the function is passed which is returning a value.
Example 1: This example uses the approach discussed above
html
<h1 style="color:green;"> GeeksforGeeks</h1><p id="GFG_UP"></p><button onclick="GFG_Fun()"> Click Here</button><p id="GFG_DOWN"></p><script> var up = document.getElementById('GFG_UP'); var down = document.getElementById('GFG_DOWN'); var func = 'return "This is return value";'; up.innerHTML = "Click on the button to create "+ "function from string.<br>FUNCTION - '" + func + "'"; // Till this point we can use 'func' as function. function GFG_Fun() { var func2 = Function(func); // Now 'func' can be used as function. down.innerHTML = func2(); }</script> |
Output:
How to create a function from a string in JavaScript ?
Approach 2:
- Use the eval() method to create a function from the string.
- It accepts the function in the form of a string and converts it to a JavaScript function.
- In this example, It takes 2 arguments and returns the sum of both numbers.
Example 2: This example uses the approach discussed above.
html
<h1 style="color:green;"> GeeksforGeeks</h1><p id="GFG_UP"></p><button onclick="GFG_Fun()"> Click Here</button><p id="GFG_DOWN"></p><script> var up = document.getElementById('GFG_UP'); var down = document.getElementById('GFG_DOWN'); var str = "var func = function (a, b) { return a + b; };"; up.innerHTML = "Click on the button to create "+ "function from string.<br>FUNCTION - '" + str + "'"; // Till this point we can use 'func' as function. function GFG_Fun() { // converting the string to function. eval(str); down.innerHTML = func(2, 5); }</script> |
Output:
How to create a function from a string in JavaScript ?
Please Login to comment...