mirror of
https://github.com/denoland/deno.git
synced 2024-12-23 07:44:48 -05:00
1f54d87789
This commit adds "ext/node" extension that implementes CommonJS module system. In the future this extension might be extended to actually contain implementation of Node compatibility layer in favor of "deno_std/node". Currently this functionality is not publicly exposed, it is available via "Deno[Deno.internal].require" namespace and is meant to be used by other functionality to be landed soon. This is a minimal first pass, things that still don't work: support for dynamic imports in CJS conditional exports
54 lines
1.5 KiB
JavaScript
54 lines
1.5 KiB
JavaScript
// deno-lint-ignore-file
|
|
|
|
/* This program is free software. It comes without any warranty, to
|
|
* the extent permitted by applicable law. You can redistribute it
|
|
* and/or modify it under the terms of the Do What The Fuck You Want
|
|
* To Public License, Version 2, as published by Sam Hocevar. See
|
|
* http://www.wtfpl.net/ for more details. */
|
|
"use strict";
|
|
module.exports = leftPad;
|
|
|
|
var cache = [
|
|
"",
|
|
" ",
|
|
" ",
|
|
" ",
|
|
" ",
|
|
" ",
|
|
" ",
|
|
" ",
|
|
" ",
|
|
" ",
|
|
];
|
|
|
|
function leftPad(str, len, ch) {
|
|
// convert `str` to a `string`
|
|
str = str + "";
|
|
// `len` is the `pad`'s length now
|
|
len = len - str.length;
|
|
// doesn't need to pad
|
|
if (len <= 0) return str;
|
|
// `ch` defaults to `' '`
|
|
if (!ch && ch !== 0) ch = " ";
|
|
// convert `ch` to a `string` cuz it could be a number
|
|
ch = ch + "";
|
|
// cache common use cases
|
|
if (ch === " " && len < 10) return cache[len] + str;
|
|
// `pad` starts with an empty string
|
|
var pad = "";
|
|
// loop
|
|
while (true) {
|
|
// add `ch` to `pad` if `len` is odd
|
|
if (len & 1) pad += ch;
|
|
// divide `len` by 2, ditch the remainder
|
|
len >>= 1;
|
|
// "double" the `ch` so this operation count grows logarithmically on `len`
|
|
// each time `ch` is "doubled", the `len` would need to be "doubled" too
|
|
// similar to finding a value in binary search tree, hence O(log(n))
|
|
if (len) ch += ch;
|
|
// `len` is 0, exit the loop
|
|
else break;
|
|
}
|
|
// pad `str`!
|
|
return pad + str;
|
|
}
|