# Binary String
> Return a string giving the literal bit representation of an [unsigned 16-bit integer][integer].
## Usage
```javascript
var toBinaryString = require( '@stdlib/number/uint16/base/to-binary-string' );
```
#### toBinaryString( x )
Returns a `string` giving the literal bit representation of an [unsigned 16-bit integer][integer].
```javascript
var Uint16Array = require( '@stdlib/array/uint16' );
var a = new Uint16Array( [ 1, 4, 9 ] );
var str = toBinaryString( a[0] );
// returns '0000000000000001'
str = toBinaryString( a[1] );
// returns '0000000000000100'
str = toBinaryString( a[2] );
// returns '0000000000001001'
```
## Notes
- Except for [typed arrays][typed-arrays], JavaScript does **not** provide native user support for [unsigned 16-bit integers][integer]. According to the [ECMAScript standard][ecma-262], `number` values correspond to [double-precision floating-point numbers][ieee754]. While this function is intended for [unsigned 16-bit integers][integer], the function will accept [floating-point][ieee754] values and represent the values **as if** they are [unsigned 16-bit integers][integer]. Accordingly, care **should** be taken to ensure that **only** nonnegative integer values less than `65536` (`2^16`) are provided.
```javascript
var str = toBinaryString( 1 );
// returns '0000000000000001'
str = toBinaryString( 4 );
// returns '0000000000000100'
str = toBinaryString( 9 );
// returns '0000000000001001'
str = toBinaryString( 65535 );
// returns '1111111111111111'
```
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var Uint16Array = require( '@stdlib/array/uint16' );
var MAX_UINT16 = require( '@stdlib/constants/uint16/max' );
var toBinaryString = require( '@stdlib/number/uint16/base/to-binary-string' );
var x;
var y;
var b;
var i;
// Generate random unsigned 16-bit integers...
x = new Uint16Array( 100 );
for ( i = 0; i < x.length; i++ ) {
x[ i ] = round( randu()*MAX_UINT16 );
}
// Convert unsigned 16-bit integers to literal bit representations...
for ( i = 0; i < x.length; i++ ) {
b = toBinaryString( x[i] );
y = parseInt( b, 2 );
console.log( 'x: %d, b: %s, y: %d', x[i], b, y );
}
```
[integer]: https://en.wikipedia.org/wiki/Integer_%28computer_science%29
[typed-arrays]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays
[ecma-262]: http://www.ecma-international.org/ecma-262/5.1/#sec-4.3.19
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985