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Chris Tate
4b8ed48a8a
`[...text]` lowered to an array literal that spread the array of text's code points: the literal's array copied the code point strings, retaining each one, and the code point array then released them. An array literal whose only element is a spread of a string is now the code points array itself, as `Array.from(text)` already was. Both are fresh arrays.
26 lines
969 B
TypeScript
26 lines
969 B
TypeScript
// Spreading strings into arrays: code points of each UTF-8 length, astral
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// pairs, lone surrogates, the empty string, and the fresh array each spread
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// returns.
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const samples = ["", "a", "abc", "é", "café", "日本語", "😀", "a😀b", "🚀🚀", "\ud800", "a\udc00b", "xé日😀"];
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for (const s of samples) {
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const chars = [...s];
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console.log(JSON.stringify(s), chars.length, JSON.stringify(chars), chars.join("|"));
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}
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// Each spread is a new array: changing one leaves the others and the string.
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const text = "héllo 😀";
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const first = [...text];
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const second = [...text];
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first.reverse();
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first.push("!");
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console.log(first.join(""), second.join(""), first === second, text);
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// The spread result is an ordinary array.
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const letters = [..."naïve"];
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letters.sort();
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console.log(letters, letters.length, Array.isArray(letters));
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console.log([..."abc"].map((c) => c.toUpperCase()).join(""));
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console.log([..."日本"].concat([..."語"]).join("-"));
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