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Note

This page has been updated for jDataView 3

Explanation

jDataView is a drop-in replacement for JavaScript's built-in DataView class, adding methods for writing strings, individual bits, arbitrary-sized integers, and more.

Installation

jDataView is published on npm, so you may install it like so:

npm add jdataview

Note that TypeScript definitions are now included in the jdataview package automatically.

Usage

jDataView functions as a drop-in replacement for the native DataView API, with extra features on top:

import { jDataView } from "jdataview";

// Construct jDataView the same way you would construct a regular DataView
// You may also pass a string or array of numbers, and jDataView will parse
// that into an ArrayBuffer automatically
const view = new jDataView(new ArrayBuffer(100));
// or you can use the static jDataView.from(..data) method
// You can also use `const view = jDataView.from(0x00, 0x01, ...etc)`

// The regular methods all work as before
view.setInt16(0, 256, true);

const msg = "Hello there";

// jDataView maintains an internal byte-cursor, which lets you use
// the API in a much more ergonomic way. For example, jDataView's
// writeXXX methods are much the same as the setXXX methods,
// but the byte-cursor position is used instead of passing an offset
view.writeString(msg);
view.writeBigInt64(2011n);

// seek(pos) changes the byte position of jDataView's internal 'cursor.' 
view.seek(0);

// You need to specify the byte length for strings (which for ASCII text is just the length)
console.log(view.getString(msg.length)); // > Hello there

// Passing an offset is optional - if you don't, jDataView uses the byte-cursor position
// jDataView also has methods that let you use bigger Numbers than JavaScript supports - you'll just lose precision
console.log(view.getInt64()); // > 2011