How to convert a floating point number to its binary representation (IEEE 754) in Javascript?

Question

What\'s the easiest way to convert a floating point number to its binary representation in Javascript? (e.g. 1.0 -> 0x3F800000).

I have tried to do it manually, and this

Answer 1

new technologies are making this easy and probably also more forward-compatible. I love extending built in prototypes, not everyone does. So feel free to modify following code to classical procedural approach:

(function() {
    function NumberToArrayBuffer() {
        // Create 1 entry long Float64 array
        return [new Float64Array([this]).buffer];
    }
    function NumberFromArrayBuffer(buffer) {
        // Off course, the buffer must be at least 8 bytes long, otherwise this is a parse error
        return new Float64Array(buffer, 0, 1)[0];
    }
    if(Number.prototype.toArrayBuffer)  {
        console.warn("Overriding existing Number.prototype.toArrayBuffer - this can mean framework conflict, new WEB API conflict or double inclusion.");
    }
    Number.prototype.toArrayBuffer = NumberToArrayBuffer;
    Number.prototype.fromArrayBuffer = NumberFromArrayBuffer;
    // Hide this methods from for-in loops
    Object.defineProperty(Number.prototype, "toArrayBuffer", {enumerable: false});
    Object.defineProperty(Number.prototype, "fromArrayBuffer", {enumerable: false});
})();

Test:

(function() {
    function NumberToArrayBuffer() {
        // Create 1 entry long Float64 array
        return new Float64Array([this.valueOf()]).buffer;
    }
    function NumberFromArrayBuffer(buffer) {
        // Off course, the buffer must be ar least 8 bytes long, otherwise this is a parse error
        return new Float64Array(buffer, 0, 1)[0];
    }
    if(Number.prototype.toArrayBuffer)  {
        console.warn("Overriding existing Number.prototype.toArrayBuffer - this can mean framework conflict, new WEB API conflict or double inclusion.");
    }
    Number.prototype.toArrayBuffer = NumberToArrayBuffer;
    Number.fromArrayBuffer = NumberFromArrayBuffer;
    // Hide this methods from for-in loops
    Object.defineProperty(Number.prototype, "toArrayBuffer", {enumerable: false});
    Object.defineProperty(Number, "fromArrayBuffer", {enumerable: false});
})();
var test_numbers = [0.00000001, 666666666666, NaN, Infinity, -Infinity,0,-0];
console.log("Conversion symethry test: ");
test_numbers.forEach(
      function(num) {
               console.log("         ", Number.fromArrayBuffer((num).toArrayBuffer()));
      }
);

console.log("Individual bytes of a Number: ",new Uint8Array((666).toArrayBuffer(),0,8));