What is JavaScript Math tanh() Function

Javascript tanh() is a built-in static method of the Math library that accepts an argument and returns the hyperbolic tangent value.

To find the hyperbolic tangent value of a given argument in JavaScript, use the Math.tanh() method.

Syntax

Math.tanh(x)

Parameter(s)

The variable x, whose hyperbolic tangent value is to be determined.

Return Value

A number is the hyperbolic tangent value.

Polyfill

Polyfill is a code that can be used in place of this method for browsers that do not support the Javascript tanh() method.

Math.tanh = Math.tanh || function (x) {
  var a = Math.exp(x), b = Math.exp(-x);
  return a == Infinity ? 1 : b == Infinity ? -1 : (a - b) / (a + b);
};

See the following figure.

 

Note

1. If the passed value is not a valid number, the method returns NaN.
2. If the passed value is ±Infinity, the method returns ±1.
3. If the passed value is ±0, the method returns the value that is passed.

Compatibility(Version and above)

1. Google Chrome v38
2. Firefox v25
3. Edge v12
4. Opera v25 
5. Safari v8
6. Android webview v38
7. Chrome for Android v38
8. Firefox for Android v25
9. Opera for Android v25
10. Safari on iOS v8
11. Samsung Internet v3.0
12. Node.js v0.12

Non-compatible with: Internet Explorer

JavaScript version: ECMAScript 6

Consider the following examples.

Javascript tanh() function example

See the following code.

// app.js

let a = 1;
let b = -1;
let c = 10;
let d = 4;
let e = -2;
let f = 2;

console.log(Math.tanh(a));
console.log(Math.tanh(b));
console.log(Math.tanh(c));
console.log(Math.tanh(d));
console.log(Math.tanh(e));
console.log(Math.tanh(f));

Output

node example1
0.7615941559557649
-0.7615941559557649
0.9999999958776927
0.999329299739067
-0.9640275800758169
0.9640275800758169

Example 2

The following example demonstrates cases where values other than valid numbers are passed.

// app.js

let a = "Hello, world";
let b;

console.log(Math.tanh(a));
console.log(Math.tanh(b));

Output

node example2
NaN
NaN

Example 3

The tanh() method cannot be used with complex arguments as only integer arguments are accepted.

// app.js


// Complex values cannot be passed as arguments as follows
// Since only integer arguments are accepted.


console.log(Math.tanh(2 + i));

Output

ReferenceError: i is not defined

Example 4

The following example demonstrates the situation when an infinite value is passed.

// app.js


let a = Infinity;
let b = -Infinity;


console.log(Math.tanh(a));
console.log(Math.tanh(b));

Output

node app
1
-1

Example 5

The following example demonstrates the situation when a positive or negative zero is passed.

// app.js

let a = 0;
let b = -0;


console.log(Math.tanh(a));
console.log(Math.tanh(b));

Output

node example5
0
-0

Example 6

The following example demonstrates the use of polyfill for this method.

// app.js

let a = 1;
let b = -1;
let c = 0;
let d = 10;
let e = Infinity;
let f = -Infinity;

function polyfill(x) {
  let a = Math.exp(x), b = Math.exp(-x);
  return a == Infinity ? 1 : b == Infinity ? -1 : (a - b) / (a + b);
}

console.log(Math.tanh(a));
console.log(Math.tanh(b));
console.log(Math.tanh(c));
console.log(Math.tanh(d));
console.log(Math.tanh(e));
console.log(Math.tanh(f));
console.log();


console.log(polyfill(a));
console.log(polyfill(b));
console.log(polyfill(c));
console.log(polyfill(d));
console.log(polyfill(e));
console.log(polyfill(f));

Output

node app
0.7615941559557649
-0.7615941559557649
0
0.9999999958776927
1
-1

0.7615941559557649
-0.7615941559557649
0
0.9999999958776926
1
-1

That’s it for this example.