index.js
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'use strict';
const BYTE_UNITS = [
'B',
'kB',
'MB',
'GB',
'TB',
'PB',
'EB',
'ZB',
'YB'
];
const BIBYTE_UNITS = [
'B',
'kiB',
'MiB',
'GiB',
'TiB',
'PiB',
'EiB',
'ZiB',
'YiB'
];
const BIT_UNITS = [
'b',
'kbit',
'Mbit',
'Gbit',
'Tbit',
'Pbit',
'Ebit',
'Zbit',
'Ybit'
];
const BIBIT_UNITS = [
'b',
'kibit',
'Mibit',
'Gibit',
'Tibit',
'Pibit',
'Eibit',
'Zibit',
'Yibit'
];
/*
Formats the given number using `Number#toLocaleString`.
- If locale is a string, the value is expected to be a locale-key (for example: `de`).
- If locale is true, the system default locale is used for translation.
- If no value for locale is specified, the number is returned unmodified.
*/
const toLocaleString = (number, locale) => {
let result = number;
if (typeof locale === 'string') {
result = number.toLocaleString(locale);
} else if (locale === true) {
result = number.toLocaleString();
}
return result;
};
module.exports = (number, options) => {
if (!Number.isFinite(number)) {
throw new TypeError(`Expected a finite number, got ${typeof number}: ${number}`);
}
options = Object.assign({bits: false, binary: false}, options);
const UNITS = options.bits ?
(options.binary ? BIBIT_UNITS : BIT_UNITS) :
(options.binary ? BIBYTE_UNITS : BYTE_UNITS);
if (options.signed && number === 0) {
return ' 0 ' + UNITS[0];
}
const isNegative = number < 0;
const prefix = isNegative ? '-' : (options.signed ? '+' : '');
if (isNegative) {
number = -number;
}
if (number < 1) {
const numberString = toLocaleString(number, options.locale);
return prefix + numberString + ' ' + UNITS[0];
}
const exponent = Math.min(Math.floor(options.binary ? Math.log(number) / Math.log(1024) : Math.log10(number) / 3), UNITS.length - 1);
// eslint-disable-next-line unicorn/prefer-exponentiation-operator
number = Number((number / Math.pow(options.binary ? 1024 : 1000, exponent)).toPrecision(3));
const numberString = toLocaleString(number, options.locale);
const unit = UNITS[exponent];
return prefix + numberString + ' ' + unit;
};