3字符串的拓展

1、JavaScri ptuxxxx u0061 uD842uDFB7 u20BB7 H 7 OxFFFF; is32Bit() / trueis32Bit(a) / false StringJromCode Point() ES5String.fromCharCode0 xFFFF String.fromCharCode(0 x20BB7) II String. froniCharCode0 xFFFF2 ES6 stringfromCodePoint(0 x20BB7) / String.fromCodePoint(0 x78, 0 xlf680, 0 x79)二二二xuD83DuDE80y

2、true stringfromCodePoint ES6 for (let codepoint of foo) console.log(codePoint) / f7/ 97/ o var text 二 String.fromCodePoint(0 x20BB7); for (let i 二 0; i text.length; i，) consolelog(texti); ” 7/ for (let i of text) console.log(i); II for at() ES5charAt0 xFFFF *abc .charAt(0) / a .charAt(0) / *uD842 ch

3、arAt atexFFFF abc .at(0) / a.at(0) / normalizeO u01Dl=u004Fu030C /falseu01Dl-length / lAu004Fu030C . length / 2 ES6normalize() u01Dl normalizeO = u004Fu030C normalizeO true normalizenormalize NFC NFD NFKCnormalize NFKD u004Fu030C*.normalize(NFC).length / 1Au004Fu030C*.nonmalizeC *NFD).length / 2 NFD

4、 包含字符，字符是否出现在开始位置和结束位置: 传统匕JavaScript只有indexOf方法，可以用來确定一个字符串是否包含在另一个 字符串中。ES6 乂提供了三种新方法。 includesO：返回布尔值，表示是否找到了参数字符串。 startsWithO：返回布尔值，表示参数字符串是否在源字符串的头部。 endsWithO：返回布尔值，表示参数字符串是否在源字符串的尾部。 includesO, startsWith() endsWith() indexOf includesO startsWithO en dsWithO var s = Hello world!; s.startsWit

5、h(* Hello) / trues.endsWith(!) / trues.includes(o) /_ true var s = Hello world!; s.startsWith(*world, 6) / trues.endsWith(Hello, 5) / trues.includes(Hello *, 6) / false nendsWith 字符串重复N次的解决：repeatO repeat xrpQ3t(3) / xxxhello.repeat(2) / hellohello*na.repeat(0) II II na.repeat(2.9) / nana repeat na.

6、repeat(Infinity) Rang eError FA repeat (-1) RangeError na var name = Bob, time = today; undefi ned hello,$name,today is $time; hello,Bob,today is today $(#result *).append( There are + basket.count + * + items in your basket, + + basket.onSale + are on sale!); $(ttresult *).append( There are $basket

7、.count items in your basket $basketonSale are on sale! ./ Tn JavaScript n is a line-feed. / Tn JavaScript this is not legal. console.log(string text line 1 string text line 2); / var name = Bob, time = today; Hello $name, how are you $time? var greeting = Yo World!; $()html( second $C #list) html( s

8、econd .trimO); function authorize(user action) if (user.hasPrivilege(action) throw new ErnorC / / authorized to do is not authorized User */ + / + action/ + . do $action.); / + is not User $ var X l;var y = to 2； .$x $y = $x + y 2 = 3 $y * 2 = $x + y * 2、 4 = 5var obj = x: 1, y: 2

9、; $obj.X + obj.y、 / 3 function fn() return Hello World; bar、 foo Hello World bar toString var msg = HellOj $place; Hello $-World- / Hello World const tmpl = addrs = $addrs.map(addr = $addr.first $addr.last 3 JoinC) const data = first: , last: Bond , first: ，Lans, last: ， ,; console. log(tnipl(data);

10、 / / Bond/ Lars/ / Hello Jack!” II let str = return + Hello $name! ;let func = new Function( name, str);func(Dack) / / let str = (name) str);func(Dack) / = Hello $name! *;let func = eval.call(null, Hello Jack! var template = % for(var i=0; i echo();for(var i=0; i data.supplies.length; i+) echo(data.

11、suppliesi); echo(*);echo(); var evalExpr = /g;var expr = /g; template = template .replace(evalExpr,八)；n echo( $1 ); n echo( ) .replace(expr, n $1 n echo(); template = echo( + template + *) template var script = (function parse(data) var output = function echo(html) output += html; $ template return

12、output;); return script; function compile(template) var evalExpr = /g; var expr = /g; ternplate = template .replace(evalExpr, n echo( $1 ); n echo( ) .replace(expr 八)；n $1 n echo( ); template = *echo( + template + ) var script = 、(function parse(data) var output = function echo(html) output += html;

13、 $ template return output; ）、； return script; compile var parse = eval(compile(template); div.innerHTML = parse( supplies: broom mop, cleaner ); / broom/ cleaner/ alert123 / alert(123) var a = 5;var b = 10; tagHello $ a + b world $ a * b 、； tagtag function tag(stringArr, valuel, value2) / / function

14、 tag(stringArr values) / tag tagvaluel tag Hello world tag(Hello - world 15, 50) var a = 5;var b = 10; function tag(s, vl, v2) console.log(s0); console.log(sl); console.log(s2); consolelog(vl); consolelog(v2); return OK; tagHello $ a + b world $ a * b、； / Hello ”/ world 7/ ”/ 15/ 50/ “OK” var total

15、= 30;var msg = passthruThe total is $total ($total*l05 with tax); function passthru(literals) var result = var i = 0; while (i literals.length) result += literaisi+; if (i arguments.length) result += argumentsi; return result; msg / The total is 30 (31.5 with tax) passthru function passthru(literals

16、, .values) var output = for (var index = 0; index values.length; index+) output += literalsindex + valuesindex; output += literalsindex return output; var message = SaferHTML$sender has sent you a message.; function SaferHTML(templateData) var s = templateData0; for (var i = 1; i arguments.length; i

17、+) var arg = String(argumentsi); / Escape special characters in the arg.replace(/) substitution. s += .replace(/g, Sgt;); / Dont escape special characters in the templates += templateDatai; return s; SaferHTML J.18n、Welcome to $siteName, you are visitor number $visitorNumber! II / var libraryHtml =

18、hashTemplate #for book in $myBooks #book.title by #book.author #end JSX $this.state.value jsxjsx java java class HelloWorldApp public static void main(String args) System.out.println(!; / Display the string. HelloWorldApp.main(); tagFirst linenSecond line function tag(strings) console Jog(strings.raw0); / First lineWnSecond line tagstringsstringsFirst linenSecond linen Stri ng.rawO ES6还为原生的String对象，提供了一个raw方法。 String.raw方法，往往用來充当模板字符串的处理函数，返回一个斜杠都被转义（即 斜杠前面再加一个斜杠）的字符串，对应于替换变量后的模板字符串。 ES6 string.raw Stringraw Hin$2+3!; / -HiWnS! String.rawHiu000A!; Hiu000A String.raw String.raw