Constnium/node_modules/es-abstract/2021/StringPad.js
2022-06-23 02:27:43 +02:00

43 lines
1.2 KiB
JavaScript

'use strict';
var GetIntrinsic = require('get-intrinsic');
var $TypeError = GetIntrinsic('%TypeError%');
var callBound = require('call-bind/callBound');
var ToLength = require('./ToLength');
var ToString = require('./ToString');
var $strSlice = callBound('String.prototype.slice');
// https://262.ecma-international.org/11.0/#sec-stringpad
module.exports = function StringPad(O, maxLength, fillString, placement) {
if (placement !== 'start' && placement !== 'end') {
throw new $TypeError('Assertion failed: `placement` must be "start" or "end"');
}
var S = ToString(O);
var intMaxLength = ToLength(maxLength);
var stringLength = S.length;
if (intMaxLength <= stringLength) {
return S;
}
var filler = typeof fillString === 'undefined' ? ' ' : ToString(fillString);
if (filler === '') {
return S;
}
var fillLen = intMaxLength - stringLength;
// the String value consisting of repeated concatenations of filler truncated to length fillLen.
var truncatedStringFiller = '';
while (truncatedStringFiller.length < fillLen) {
truncatedStringFiller += filler;
}
truncatedStringFiller = $strSlice(truncatedStringFiller, 0, fillLen);
if (placement === 'start') {
return truncatedStringFiller + S;
}
return S + truncatedStringFiller;
};