Read/Write bytes of float in JS

javascript serialization floating-point math ieee-754
Michael Pliskin picture Michael Pliskin · Dec 11, 2010 · Viewed 22.3k times · Source

Is there any way I can read bytes of a float value in JS? What I need is to write a raw FLOAT or DOUBLE value into some binary format I need to make, so is there any way to get a byte-by-byte IEEE 754 representation? And same question for writing of course.

Answer

Eric picture Eric · May 12, 2012

You can do it with typed arrays:

var buffer = new ArrayBuffer(4);
var intView = new Int32Array(buffer);
var floatView = new Float32Array(buffer);

floatView[0] = Math.PI
console.log(intView[0].toString(2)); //bits of the 32 bit float

Or another way:

var view = new DataView(new ArrayBuffer(4));
view.setFloat32(0, Math.PI);
console.log(view.getInt32(0).toString(2)); //bits of the 32 bit float

Not sure what browser support is like though

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