Nucleic Phosphate Modifier

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    4.3.0 • Public • Published

    Amazon Ion JavaScript

    An implementation of Amazon Ion for JavaScript written in TypeScript.

    NPM Version License Documentation

    This package is tested with Node JS major versions 10, 12, 14, and 16. While this library should be usable within browsers that support ES5+, please note that it is not currently being tested in any browser environments.

    Getting Started

    You can use this library either as a Node.js module or inside an HTML page.


    1. Add ion-js and jsbi to your dependencies using npm

      npm install --save ion-js jsbi
    2. Use the library to read/write Ion data. Here is an example that reads Ion data from a JavaScript string:

      let ion = require("ion-js");
      // Reading
      let ionData = '{ greeting: "Hello", name: "Ion" }';
      let value = ion.load(ionData);
      console.log(value.greeting + ", " + + "!");
      // Writing
      let ionText = ion.dumpText(value);
      console.log("Serialized Ion: " + ionText);

      For more examples, see the Ion DOM README.

    Try it yourself.

    Note: if your package's public interface exposes part of this library, this library should be specified as a peer dependency in your package's package.json file. Otherwise, packages that depend on your package and this library may experience unexpected behavior, as two installations of this library (even if the same version) are not designed or tested to behave correctly.

    Web Browser

    You can include the Ion-js bundle (ES5 compatible) using the URLs

    These will create and initialize window.ion which has the same exact API as our npm package. Here is an example

      <meta charset="UTF-8"/>
      <script src="scripts/ion-bundle.min.js"></script>
      <!-- more HTML/JS code that can now use `window.ion` to create/write Ion -->


    TypeDoc generated documentation can be found at here. Please note that anything not documented in the the API documentation is not supported for public use and is subject to change in any version.

    Git Setup

    This repository contains a git submodule called ion-tests, which holds test data used by ion-js's unit tests.

    The easiest way to clone the ion-js repository and initialize its ion-tests submodule is to run the following command.

    $ git clone --recursive ion-js

    Alternatively, the submodule may be initialized independently from the clone by running the following commands.

    $ git submodule init
    $ git submodule update


    Use npm to setup the dependencies. In the project directory you can run the following:

    $ npm install

    Building the package can be done with the release script (which runs the tests).

    $ npm run release

    Tests can be run using npm as well

    $ npm test

    This package uses Grunt for its build tasks. For convenience, you may want to install this globally:

    $ npm -g install grunt-cli
    $ grunt release

    Or you could use the locally installed Grunt:

    $ ./node_modules/.bin/grunt release

    Build Output

    The build above will compile the library into the dist directory. This directory has subdirectories of the form <module type>/<target ES version>. In general, we target ES6 and rely on polyfills to support earlier versions.

    • dist/es6/es6 - Targets the ES6 module system and ES6
    • dist/commonjs/es6 - Targets the CommonJS module system and ES6
    • dist/amd/es6 - Targets the AMD module system and ES6

    A distribution using browserify and babelify creates a browser friendly polyfilled distribution targeting ES5: at dist/browser/js/ion-bundle.js.

    Ion Specification Support

    Types IonText IonBinary Limitations
    null yes yes none
    bool yes yes none
    int yes yes underscores, binary digits
    float yes yes underscores
    decimal yes yes none
    timestamp yes yes none
    string yes yes none
    symbol yes yes $0, symbol tokens
    blob yes yes none
    clob yes yes none
    struct yes yes none
    list yes yes none
    sexp yes yes none
    annotations yes yes none
    local symbol tables yes yes none
    shared symbol tables no yes none


    • test/iontests.ts defines multiple skipList variables referencing test vectors that are not expected to work at this time.

    • ion-js supports shared symbol table for Ion Binary. Below is an example of how shared symbol table can be used here:

    // Create a SharedSymbolTable with the desired strings
    let sharedSymbolTable = new SharedSymbolTable('foo', 1, ['id', 'name']);
    // Define an import chain
    // The system symbol table does not import any other tables (`null` below)
    let systemSymbolTableImport = new Import(null, getSystemSymbolTable());
    // The shared symbol table imports the system symbol table
    let sharedSymbolTableImport = new Import(systemSymbolTableImport, sharedSymbolTable);
    // Create a local symbol table that imports the shared symbol table
    let localSymbolTable = new LocalSymbolTable(sharedSymbolTableImport);
    // Create a writer that uses our new local symbol table
    let writer = new BinaryWriter(localSymbolTable, new Writeable());
    // Write id and name fields in a struct
    // Create a catalog with shared symbol table
    let catalog = new Catalog();
    // Create a reader with catalog
    let bytes = writer.getBytes();
    let reader = new BinaryReader(new BinarySpan(bytes), catalog);




    This library is licensed under Apache License version 2.0


    For more information about Ion or its other implementation, please see:


    npm i ion-js

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