# From Binary String
> Create a [double-precision floating-point number][ieee754] from a [literal bit representation][@stdlib/number/float64/base/to-binary-string].
## Usage
```javascript
var fromBinaryString = require( '@stdlib/number/float64/base/from-binary-string' );
```
#### fromBinaryString( bstr )
Creates a [double-precision floating-point number][ieee754] from a [literal bit representation][@stdlib/number/float64/base/to-binary-string].
```javascript
var bstr = '0100000000010000000000000000000000000000000000000000000000000000';
var val = fromBinaryString( bstr );
// returns 4.0
bstr = '0100000000001001001000011111101101010100010001000010110100011000';
val = fromBinaryString( bstr );
// returns 3.141592653589793
bstr = '1111111111100001110011001111001110000101111010111100100010100000';
val = fromBinaryString( bstr );
// returns -1.0e308
```
The function handles [subnormals][subnormals].
```javascript
var bstr = '1000000000000000000000000000000000000000000000000001100011010011';
var val = fromBinaryString( bstr );
// returns -3.14e-320
bstr = '0000000000000000000000000000000000000000000000000000000000000001';
val = fromBinaryString( bstr );
// returns 5.0e-324
```
The function handles special values.
```javascript
var bstr = '0000000000000000000000000000000000000000000000000000000000000000';
var val = fromBinaryString( bstr );
// returns 0.0
bstr = '1000000000000000000000000000000000000000000000000000000000000000';
val = fromBinaryString( bstr );
// returns -0.0
bstr = '0111111111111000000000000000000000000000000000000000000000000000';
val = fromBinaryString( bstr );
// returns NaN
bstr = '0111111111110000000000000000000000000000000000000000000000000000';
val = fromBinaryString( bstr );
// returns Infinity
bstr = '1111111111110000000000000000000000000000000000000000000000000000';
val = fromBinaryString( bstr );
// returns -Infinity
```
## Examples
```javascript
var randu = require( '@stdlib/random/base/randu' );
var round = require( '@stdlib/math/base/special/round' );
var pow = require( '@stdlib/math/base/special/pow' );
var toBinaryString = require( '@stdlib/number/float64/base/to-binary-string' );
var fromBinaryString = require( '@stdlib/number/float64/base/from-binary-string' );
var frac;
var sign;
var exp;
var b;
var x;
var y;
var i;
// Convert random numbers to literal bit representations and then convert them back...
for ( i = 0; i < 100; i++ ) {
if ( randu() < 0.5 ) {
sign = -1.0;
} else {
sign = 1.0;
}
frac = randu() * 10.0;
exp = round( randu()*100.0 );
if ( randu() < 0.5 ) {
exp = -exp;
}
x = sign * frac * pow( 2.0, exp );
b = toBinaryString( x );
y = fromBinaryString( b );
console.log( '%d => %s => %d', x, b, y );
console.log( x === y );
}
```
[ieee754]: https://en.wikipedia.org/wiki/IEEE_754-1985
[subnormals]: https://en.wikipedia.org/wiki/Denormal_number
[@stdlib/number/float64/base/to-binary-string]: https://github.com/stdlib-js/number/tree/main/float64/base/to-binary-string
[@stdlib/number/float32/base/from-binary-string]: https://github.com/stdlib-js/number/tree/main/float32/base/from-binary-string