JavaScript Math.log1p() Method

The Javascript Math.log1p() is an inbuilt function in JavaScript that gives the value of the natural logarithm of 1 + p number. The natural logarithm is of base e, where e is an irrational and transcendental number approximately equal to 2.718. 

Syntax:

Math.log1p(1 + p)

Let’s see some JavaScript code on this function:

Example 1: In this example, we will find the logarithms of some basic numbers.

javascript

<script>
    // Different numbers are being taken
    // as the parameter of the function.
    console.log(Math.log1p(1000) + "<br>");
    console.log(Math.log1p(12) + "<br>");
    console.log(Math.log1p(26) + "<br>");
    console.log(Math.log1p(5));
</script>

Output:

6.90875477931522
2.5649493574615367
3.295836866004329
1.791759469228055

Example 2: In this example, we will use a for loop to get the logarithms of numbers from 1 to 19 with an increment of 3.

javascript

<script>
    // Taken parameter from 1 to 19 incremented by 3.
    for (i = 1; i < 20; i += 3)
    {
        console.log(Math.log1p(i) + "<br>");
    }
</script>

Output:

0.6931471805599453
1.6094379124341003
2.0794415416798357
2.3978952727983707
2.639057329615259
2.833213344056216
2.995732273553991

Errors and exceptions: Parameters for this function should always be a number otherwise it returns NaN i.e, not a number when its parameter is taken as a string.

Example 1: Here NaN comes in output as we have passed a string in the Math.log1p() function.

javascript

<script>
    // Parameters for this function should always be a
    // number otherwise it return NaN i.e, not a number
    // when its parameter taken as string.
    console.log(Math.log1p("gfg"));
</script>

Output:

 NaN

Example 2: This function gives an error when its parameter is taken as a complex number because it accepts only integer value as the parameter. 

javascript

<script>
    // Parameters can never be a complex number because
    // it accept only integer value as the parameter.
    console.log(Math.log1p(1 + 2i));
</script>

Output:

Error: Invalid or unexpected token

Example 3: This function returns NaN i.e, not a number if the parameter is less than -1 because the number should be any positive number i.e, greater than 0. 

javascript

<script>
    // This function return NaN i.e, not a number
    // if the parameter is less
    // than -1 because number should be
    // any positive number i.e, greater than 0.
    console.log(Math.log1p(-2));
</script>

• Output:

 NaN

We have a complete list of Javascript Math Object methods, to check those please go through Javascript Math Object Complete reference article.

Supported Browsers: The browsers supported by JavaScript Math.log1p( ) function are listed below:

• Google Chrome 38 and above
• Edge 12 and above
• Firefox 25 and above
• Opera 25 and above
• Safari 8 and above