JavaScript has a Unicode problem · Mathias Bynens
The way JavaScript handles Unicode is… surprising, to say the least. This write-up explains the pain points associated with Unicode in JavaScript, provides solutions for common problems, and explains how the ECMAScript 6 standard improves the situation. Unicode basics Before we take a closer look at JavaScript, let’s make sure we’re all on the same page when it comes to Unicode. It’s easiest to th
Understanding ECMAScript 6 arrow functions - Human Who Codes
One of the most interesting new parts of ECMAScript 6 are arrow functions. Arrow functions are, as the name suggests, functions defined with a new syntax that uses an “arrow†(=>) as part of the syntax. However, arrow functions behave differently than traditional JavaScript functions in a number of important ways: Lexical this binding – The value of this inside of the function is determined by whe
JavaScriptã®+演算åã®è¬ŽæŒ™å‹•ã«è¿«ã‚‹ » nmi.jp
console.log(+[]); // 0 console.log(+[3]); // 3 console.log(+[null]); // 0 console.log(+[undefined]); // 0 console.log(+["3"]); // 3 console.log(+[1,2]); // NaN console.log(+[true]); // NaN console.log(+[false]); // NaN ãªãœã“ã®ã‚ˆã†ãªå‡¦ç†ã«ãªã‚‹ã®ã‹ã€JavaScriptã®ä»•æ§˜æ›¸ï¼ˆECMA Script Specification 5th）ã‹ã‚‰èª¬æ˜Žã—ã¦ã¿ã¾ã—ょã†ã€‚ ã¾ãšæœ€åˆã€å˜é …+演算å（Unary + Operator）を評価ã™ã‚‹éš›ã«ã€ToNumberを呼ã³å‡ºã™ã®ã¯å‰è¿°ã—ãŸã¨ãŠã‚Šã§ã™ã€‚仕様書ã®ï¼ˆ11.4.6）ã«æ›¸ã‹ã‚Œã¦ã„ã¾ã™ã€‚ã§ã¯ToNumberã¨ã¯ã©ã®ã‚ˆã†ãªå‡¦ç†ã§ã—ょã†ã‹ã€‚
Valid JavaScript variable names in ES5 · Mathias Bynens
Note: This article is based on the ECMAScript 5 specification. For the updated ES2015 version, see Valid JavaScript variable names in ES2015. Did you know var π = Math.PI; is syntactically valid JavaScript? I thought this was pretty cool, so I decided to look into which Unicode glyphs are allowed in JavaScript variable names, or identifiers as the ECMAScript specification calls them. Reserved word
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