[Term Entry] JavaScript Number Methods: .isSafeInteger()

* Add .isSafeInteger() term entry for JavaScript number methods

* Add .isSafeInteger() term entry for JavaScript number methods

* Update isSafeInteger.md

* Update yarn.lock

* Update isSafeInteger.md

* Update isSafeInteger.md

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Author: onealanil

content/javascript/concepts/number-methods/terms/isSafeInteger/isSafeInteger.md

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+---
+Title: '.isSafeInteger()'
+Description: 'Checks whether the passed value is a safe integer.'
+Subjects:
+  - 'Computer Science'
+  - 'Web Development'
+Tags:
+  - 'Methods'
+  - 'Numbers'
+CatalogContent:
+  - 'introduction-to-javascript'
+  - 'paths/front-end-engineer-career-path'
+---
+
+The **`.isSafeInteger()`** method is a static method of the `Number` object in JavaScript which determines whether the provided value is a safe integer: an integer that can be exactly represented using the IEEE-754 double-precision format.
+
+A safe integer satisfies:
+
+$$
+-(2^{53} - 1) \leq \text{value} \leq 2^{53} - 1
+$$
+
+If the condition holds, the method returns `true`, otherwise, it returns `false`.
+
+## Syntax
+
+```pseudo
+Number.isSafeInteger(value);
+```
+
+**Parameters:**
+
+- `value`: The value to be tested for being a safe integer.
+
+**Return value:**
+
+Returns `true` if the given `value` is of type `number`, is an integer, and is within the safe integer range (`-(2^53 - 1) to 2^53 - 1`). Otherwise, it returns `false`.
+
+## Example
+
+This example demonstrates how `.isSafeInteger()` returns `true` for integers and `false` for non-integers or values outside the safe range:
+
+```js
+console.log(Number.isSafeInteger(10));
+console.log(Number.isSafeInteger(3.14));
+console.log(Number.isSafeInteger(Math.pow(2, 53)));
+console.log(Number.isSafeInteger(2 ** 53 - 1));
+```
+
+The output of this code is:
+
+```shell
+true
+false
+false
+true
+```
+
+## Codebyte Example
+
+This codebyte tests various values to show how the method handles whole numbers, decimals, and edge cases at the limits of JavaScript’s safe integer range:
+
+```codebyte/javascript
+console.log(Number.isSafeInteger(100));
+console.log(Number.isSafeInteger(3.5));
+console.log(Number.isSafeInteger(2 ** 53 - 1));
+console.log(Number.isSafeInteger(2 ** 53));
+```