TypeScript: const n=1ã¨const n:1=1ã¯ä½•ãŒé•ã†ã®ã‹ã€ãªãœé•ã†ã®ã‹ä¸¡è€…ã®é•ã„ エディタã§ãƒ›ãƒãƒ¼ã™ã‚‹ã¨ã„ãšã‚Œã‚‚ 1 ã¨ã„ã†åž‹ãŒè¡¨ç¤ºã•ã‚Œã€ä¸€è¦‹åŒã˜ã“ã¨ã‚’ã—ã¦ã„るよã†ã«æ€ãˆã‚‹ã‹ã‚‚ã—ã‚Œã¾ã›ã‚“。ã—ã‹ã—ã€ã“れらã¯æ˜Žç¢ºã«é•ã†åž‹ã‚’æŒã¡ã¾ã™ã€‚ ãã®å‰ã«ã€ã™ã¹ã¦ã®å¤‰æ•°ã¯ã€ãã®å¤‰æ•°ã®åž‹ã¨ã¯åˆ¥ã«ã€Type Narrowingã¨ã„ã†ä»•çµ„ã¿ã«ã‚ˆã£ã¦ä¸€æ™‚çš„ã«åˆ¥ã®åž‹ã¨ã—ã¦å–り扱ã†æ©Ÿèƒ½ãŒã‚ã‚Šã¾ã™ã€‚ ãã‚Œãžã‚Œã€ä»®ã« global type 㨠narrowed type ã¨å‘¼ã¶ã“ã¨ã«ã—ã¾ã™ã€‚ ã™ã‚‹ã¨ã€const n: 1 = 1 㯠(global type, narrowed type) = (1, 1) ã§ã™ãŒã€const n = 1 㯠(global type, narrowed type) = (number, 1) ã§ã™ã€‚ã“ã‚Œã¯ä»¥ä¸‹ã®ã‚ˆã†ãªã‚³ãƒ¼ãƒ‰ã§ç¢ºèªãŒã§ãã¾ã™ã€‚ const n: 1 = 1; const getN = () => n; // inferred as () =
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