39 lines
1.6 KiB
JavaScript
39 lines
1.6 KiB
JavaScript
"use strict";
|
|
Object.defineProperty(exports, "__esModule", { value: true });
|
|
exports.ComputeExponent = ComputeExponent;
|
|
var tslib_1 = require("tslib");
|
|
var decimal_js_1 = tslib_1.__importDefault(require("decimal.js"));
|
|
var ComputeExponentForMagnitude_1 = require("./ComputeExponentForMagnitude");
|
|
var FormatNumericToString_1 = require("./FormatNumericToString");
|
|
/**
|
|
* The abstract operation ComputeExponent computes an exponent (power of ten) by which to scale x
|
|
* according to the number formatting settings. It handles cases such as 999 rounding up to 1000,
|
|
* requiring a different exponent.
|
|
*
|
|
* NOT IN SPEC: it returns [exponent, magnitude].
|
|
*/
|
|
function ComputeExponent(internalSlots, x) {
|
|
if (x.isZero()) {
|
|
return [0, 0];
|
|
}
|
|
if (x.isNegative()) {
|
|
x = x.negated();
|
|
}
|
|
var magnitude = x.log(10).floor();
|
|
var exponent = (0, ComputeExponentForMagnitude_1.ComputeExponentForMagnitude)(internalSlots, magnitude);
|
|
// Preserve more precision by doing multiplication when exponent is negative.
|
|
x = x.times(decimal_js_1.default.pow(10, -exponent));
|
|
var formatNumberResult = (0, FormatNumericToString_1.FormatNumericToString)(internalSlots, x);
|
|
if (formatNumberResult.roundedNumber.isZero()) {
|
|
return [exponent, magnitude.toNumber()];
|
|
}
|
|
var newMagnitude = formatNumberResult.roundedNumber.log(10).floor();
|
|
if (newMagnitude.eq(magnitude.minus(exponent))) {
|
|
return [exponent, magnitude.toNumber()];
|
|
}
|
|
return [
|
|
(0, ComputeExponentForMagnitude_1.ComputeExponentForMagnitude)(internalSlots, magnitude.plus(1)),
|
|
magnitude.plus(1).toNumber(),
|
|
];
|
|
}
|