Package Exports

as-string-sink

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (as-string-sink) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

String Sink

An efficient dynamically sized string buffer (aka String Builder) for AssemblyScript.

Interface

class StringSink {
  static withCapacity(capacity: i32)

  constructor(initial: string = "", capacity: i32 = 64)

  get length(): i32
  get capacity(): i32

  write(src: string, start?: i32, end?: i32): void
  writeLn(src: string, start?: i32, end?: i32): void
  writeCodePoint(code: i32): void

  shrink(): void
  clear(): void

  toString(): string
}

Benchmark Results

StringSink can be up to 8700 times faster than native string concatenation!

100 strings:
------------
String += JS:  0.013 ms
String += AS:  0.017 ms
StringSink AS: 0.0034 ms

50,000 strings:
---------------
String += JS:  3.89 ms
String += AS:  1219.44 ms
StringSink AS: 0.54 ms

200,000 strings:
----------------
String += JS:  11.29 ms
String += AS:  18360.15 ms
StringSink AS: 2.28 ms

Usage 1. String accumulation (+=)

non efficient example:

function toList(arr: string[]): string {
  let res = "";
  for (let i = 0, len = arr.length; i < len; i++) {
    res += arr[i] + "\n";
  }
  return res;
}

efficient with StringSink:

function toList(arr: string[]): string {
  let res = new StringSink();
  for (let i = 0, len = arr.length; i < len; i++) {
    res.write(arr[i] + "\n");
  }
  return res.toString();
}

even more efficient:

function toList(arr: string[]): string {
  let res = new StringSink();
  for (let i = 0, len = arr.length; i < len; i++) {
    res.writeLn(arr[i]);
  }
  return res.toString();
}

Usage 2. String accumulation (+=) only part of string

non efficient example:

function toListSliced(arr: string[]): string {
  let res = "";
  for (let i = 0, len = arr.length; i < len; i++) {
    res += arr[i].substring(1, 3);
  }
  return res;
}

more efficient with StringSink:

function toListSliced(arr: string[]): string {
  let res = new StringSink();
  for (let i = 0, len = arr.length; i < len; i++) {
    res.write(arr[i], 1, 3);
  }
  return res.toString();
}