assemblyscript-json

!npm version !npm downloads per month

JSON encoder / decoder for AssemblyScript.

Special thanks to https://github.com/MaxGraey/bignum.wasm for basic unit testing infra for AssemblyScript.

Installation

assemblyscript-json is available as a npm package. You can install assemblyscript-json in your AssemblyScript project by running:

npm install --save assemblyscript-json

Usage

$3

``typescript
import { JSON } from "assemblyscript-json";

// Parse an object using the JSON object
let jsonObj: JSON.Obj = (JSON.parse('{"hello": "world", "value": 24}'));

// We can then use the .getX functions to read from the object if you know it's type
// This will return the appropriate JSON.X value if the key exists, or null if the key does not exist
let worldOrNull: JSON.Str | null = jsonObj.getString("hello"); // This will return a JSON.Str or null
if (worldOrNull != null) {
// use .valueOf() to turn the high level JSON.Str type into a string
let world: string = worldOrNull.valueOf();
}

let numOrNull: JSON.Num | null = jsonObj.getNum("value");
if (numOrNull != null) {
// use .valueOf() to turn the high level JSON.Num type into a f64
let value: f64 = numOrNull.valueOf();
}

// If you don't know the value type, get the parent JSON.Value
let valueOrNull: JSON.Value | null = jsonObj.getValue("hello");
if (valueOrNull != null) {
let value = valueOrNull;

// Next we could figure out what type we are
if(value.isString) {
// value.isString would be true, so we can cast to a string
let innerString = (value).valueOf();
let jsonString = (value).stringify();

// Do something with string value
}
}
`

$3


`typescript
import { JSONEncoder } from "assemblyscript-json";

// Create encoder
let encoder = new JSONEncoder();

// Construct necessary object
encoder.pushObject("obj");
encoder.setInteger("int", 10);
encoder.setString("str", "");
encoder.popObject();

// Get serialized data
let json: Uint8Array = encoder.serialize();

// Or get serialized data as string
let jsonString: string = encoder.stringify();

assert(jsonString, '"obj": {"int": 10, "str": ""}'); // True!
`

$3

`typescript
import { JSONDecoder, JSONHandler } from "assemblyscript-json";

// Events need to be received by custom object extending JSONHandler.
// NOTE: All methods are optional to implement.
class MyJSONEventsHandler extends JSONHandler {
setString(name: string, value: string): void {
// Handle field
}

setBoolean(name: string, value: bool): void {
// Handle field
}

setNull(name: string): void {
// Handle field
}

setInteger(name: string, value: i64): void {
// Handle field
}

setFloat(name: string, value: f64): void {
// Handle field
}

pushArray(name: string): bool {
// Handle array start
// true means that nested object needs to be traversed, false otherwise
// Note that returning false means JSONDecoder.startIndex need to be updated by handler
return true;
}

popArray(): void {
// Handle array end
}

pushObject(name: string): bool {
// Handle object start
// true means that nested object needs to be traversed, false otherwise
// Note that returning false means JSONDecoder.startIndex need to be updated by handler
return true;
}

popObject(): void {
// Handle object end
}
}

// Create decoder
let decoder = new JSONDecoder(new MyJSONEventsHandler());

// Create a byte buffer of our JSON. NOTE: Deserializers work on UTF8 string buffers.
let jsonString = '{"hello": "world"}';
let jsonBuffer = Uint8Array.wrap(String.UTF8.encode(jsonString));

// Parse JSON
decoder.deserialize(jsonBuffer); // This will send events to MyJSONEventsHandler
``

Feel free to look through the tests for more usage examples.

Reference Documentation

Reference API Documentation can be found in the docs directory.

License

MIT