diff options
Diffstat (limited to 'src/node_modules/es-abstract/2020/StringPad.js')
-rw-r--r-- | src/node_modules/es-abstract/2020/StringPad.js | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/src/node_modules/es-abstract/2020/StringPad.js b/src/node_modules/es-abstract/2020/StringPad.js new file mode 100644 index 0000000..edc06a7 --- /dev/null +++ b/src/node_modules/es-abstract/2020/StringPad.js @@ -0,0 +1,43 @@ +'use strict'; + +var GetIntrinsic = require('../GetIntrinsic'); + +var $TypeError = GetIntrinsic('%TypeError%'); + +var callBound = require('../helpers/callBound'); + +var ToLength = require('./ToLength'); +var ToString = require('./ToString'); + +var $strSlice = callBound('String.prototype.slice'); + +// https://tc39.es/ecma262/2020/#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; +}; |