| 1 | // Computes the decimal coefficient and exponent of the specified number x with
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| 2 | // significant digits p, where x is positive and p is in [1, 21] or undefined.
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| 3 | // For example, formatDecimal(1.23) returns ["123", 0].
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| 4 | export default function(x, p) {
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| 5 | if ((i = (x = p ? x.toExponential(p - 1) : x.toExponential()).indexOf("e")) < 0) return null; // NaN, ±Infinity
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| 6 | var i, coefficient = x.slice(0, i);
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| 7 |
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| 8 | // The string returned by toExponential either has the form \d\.\d+e[-+]\d+
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| 9 | // (e.g., 1.2e+3) or the form \de[-+]\d+ (e.g., 1e+3).
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| 10 | return [
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| 11 | coefficient.length > 1 ? coefficient[0] + coefficient.slice(2) : coefficient,
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| 12 | +x.slice(i + 1)
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| 13 | ];
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| 14 | }
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