[Bug] ArrayBuffer does not have length property

[jtenner]

There is an issue with the toHaveLength() assertion that should work with ArrayBuffers.

ERROR TS2339: Property 'length' does not exist on type '~lib/arraybuffer/ArrayBuffer'.

       length = actual.length;
                       ~~~~~~
 in node_modules/as-pect/assembly/internal/comparison/lengthComparison.ts(34,22)

Way to reproduce:

expect<ArrayBuffer>(buffer).toHaveLength(100, "Some expectation.");

[willemneal]

This is because ArrayBuffer doesn't have a length property any more as that is meant for different views with various element widths. Use byteLength or cast it as a Uint8Array.

@sealed export class ArrayBuffer {

  static isView<T>(value: T): bool {
    if (value) {
      if (value instanceof Int8Array) return true;
      if (value instanceof Uint8Array) return true;
      if (value instanceof Uint8ClampedArray) return true;
      if (value instanceof Int16Array) return true;
      if (value instanceof Uint16Array) return true;
      if (value instanceof Int32Array) return true;
      if (value instanceof Uint32Array) return true;
      if (value instanceof Int64Array) return true;
      if (value instanceof Uint64Array) return true;
      if (value instanceof Float32Array) return true;
      if (value instanceof Float64Array) return true;
      if (value instanceof DataView) return true;
    }
    return false;
  }

  constructor(length: i32) {
    if (<u32>length > <u32>BLOCK_MAXSIZE) throw new RangeError(E_INVALIDLENGTH);
    var buffer = __alloc(<usize>length, idof<ArrayBuffer>());
    memory.fill(buffer, 0, <usize>length);
    return changetype<ArrayBuffer>(buffer); // retains
  }

  get byteLength(): i32 {
    return changetype<BLOCK>(changetype<usize>(this) - BLOCK_OVERHEAD).rtSize;
  }

  slice(begin: i32 = 0, end: i32 = BLOCK_MAXSIZE): ArrayBuffer {
    var length = this.byteLength;
    begin = begin < 0 ? max(length + begin, 0) : min(begin, length);
    end   = end   < 0 ? max(length + end  , 0) : min(end  , length);
    var outSize = <usize>max(end - begin, 0);
    var out = __alloc(outSize, idof<ArrayBuffer>());
    memory.copy(out, changetype<usize>(this) + <usize>begin, outSize);
    return changetype<ArrayBuffer>(out); // retains
  }

  toString(): string {
    return "[object ArrayBuffer]";
  }
}

[jtenner]

I'm aware of this. Have you seen the lengthComparison function in the comparison folder?

[jtenner]

Closed via AssemblyScript/assemblyscript#681