expand-tabs-to-spaces

expand tabs to spaces

Install

npm install expand-tabs-to-spaces

Usage & Api

/*
expand tabs to spaces

expandTabs(str, options | tabSize )
	options
		.tabSize
			tab spaces size, default 4.
		.lengthFunc
			a user-defined function returned the string length, for FullWidth codeset.
				function(str){ ...; return length; }
			if empty, use the str.length by default.
*/
var expandTabs = require("expand-tabs-to-spaces");

//a simple HalfWidth length function for test, refer halfwidth-kit/length @ npm
var halfWidthLength = function (str) {
	return str.length + str.replace(/[\u0000-\u00ff\uFF61-\uFF9F\uFFE8-\uFFEE]+/g, "").length
}

expandTabs("a") === "a" &&
expandTabs("\ta") === "    a" &&
expandTabs("\t\ta") === "        a" &&
expandTabs("\ta\tb") === "    a   b" &&
expandTabs("\taa\tb") === "    aa  b" &&
expandTabs("\taaa\tb") === "    aaa b" &&
expandTabs("\taaaa\tb") === "    aaaa    b" &&

expandTabs("\ta\tb", 8) === "        a       b" &&
expandTabs("\ta\tb", { tabSize: 8 }) === "        a       b" &&

expandTabs("\ta中文\tb", { lengthFunc: halfWidthLength }) === "    a中文   b" &&
expandTabs("\t中文\tb", { lengthFunc: halfWidthLength }) === "    中文    b" &&
expandTabs("中\t文\tb", { lengthFunc: halfWidthLength }) === "中  文  b" &&

//multiple lines
expandTabs("\n\n\taaaa\tb\r\r中\t文\tb\n\r\ta中文\tb", { lengthFunc: halfWidthLength })
	=== "\n\n    aaaa    b\r\r中  文  b\n\r    a中文   b" &&