26 lines
519 B
JavaScript
26 lines
519 B
JavaScript
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const sequence = fn => {
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return {
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take: n => {
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const res = [];
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for (let i = 0; i < n; ++i) {
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res[i] = fn(i);
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}
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return res;
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},
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takeWhile: pred => {
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const res = [];
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for (let i = 0; 1; ++i) {
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const val = fn(i);
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if (!pred(val)) break;
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res[i] = fn(i);
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}
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return res;
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},
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};
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};
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sequence(n => n).takeWhile(n => n < 10); // [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
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sequence(n => n * n).take(10); // [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
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