Use of bitwise OR operation in TypedArray.prototype.subarray() call in Javascript

Asked Jul 22 '20 at 05:06

Active Jul 22 '20 at 05:17

Viewed 55 times

The following code is from https://developer.mozilla.org/en-US/docs/Web/API/TextEncoder/encodeInto under heading "Encode Into A Specific Position".

var encoder = new TextEncoder;
function encodeIntoAtPosition(string, u8array, position) {
    return encoder.encodeInto(string, position ? u8array.subarray(position|0) : u8array);
}

var u8array = new Uint8Array(8);
encodeIntoAtPosition("hello", u8array, 2);
console.log( "" + u8array.join() ); // 0,0,104,101,108,108,111,0

In encodeIntoAPosition, what is the reason for position|0?

Here are some results for bitwise OR operations.

console.info([ 2|0, 2.5|0, 'z'|0, 'abc'|0, -2|0, -2.5|0 ]);

Thanks.

asked Jul 22 '20 at 05:06

Logan Lee

1

It coerces it to a number and truncates it. – Unmitigated Jul 22 '20 at 05:07
1

Does this answer your question? [using bitwise OR in javascript to convert to integer](https://stackoverflow.com/questions/12695504/using-bitwise-or-in-javascript-to-convert-to-integer) – jdaz Jul 22 '20 at 05:12
@jdaz I'll have a read at https://stackoverflow.com/questions/596467/how-do-i-convert-a-float-number-to-a-whole-number-in-javascript thx – Logan Lee Jul 22 '20 at 05:15
@hev1 exactly. thx – Logan Lee Jul 22 '20 at 05:18

Use of bitwise OR operation in TypedArray.prototype.subarray() call in Javascript

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