Require Node.js 8, add TypeScript definition (#15)

.gitattributes

@@ -1,2 +1 @@
-* text=auto
-*.js text eol=lf
+* text=auto eol=lf

.travis.yml

@@ -1,4 +1,5 @@
 language: node_js
 node_js:
+  - '12'
+  - '10'
   - '8'
-  - '6'

index.d.ts

@@ -0,0 +1,56 @@
+declare const roundTo: {
+	/**
+	Round the decimals with [`Math.round`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/round).
+
+	Numbers are rounded to a specific number of fractional digits. Specifying a negative `precision` will round to any number of places to the left of the decimal.
+
+	@param number - Number to adjust.
+	@param precision - (Integer) Number of decimal places.
+
+	@example
+	```
+	import roundTo = require('round-to');
+
+	roundTo(1.234, 2);
+	//=> 1.23
+
+	roundTo(1234.56, -2);
+	//=> 1200
+	```
+	*/
+	(number: number, precision: number): number;
+
+	/**
+	Round up the decimals with [`Math.ceil`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/ceil).
+
+	@param number - Number to adjust.
+	@param precision - (Integer) number of decimal places.
+
+	@example
+	```
+	import roundTo = require('round-to');
+
+	roundTo.up(1.234, 2);
+	//=> 1.24
+	```
+	*/
+	up(number: number, precision: number): number;
+
+	/**
+	Round down the decimals with [`Math.floor`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor).
+
+	@param number - Number to adjust.
+	@param precision - (Integer) number of decimal places.
+
+	@example
+	```
+	import roundTo = require('round-to');
+
+	roundTo.down(1.234, 2);
+	//=> 1.23
+	```
+	*/
+	down(number: number, precision: number): number;
+};
+
+export = roundTo;

index.js

@@ -1,30 +1,31 @@
 'use strict';
 
-function round(method, input, precision) {
-	if (typeof input !== 'number') {
+function round(method, number, precision) {
+	if (typeof number !== 'number') {
 		throw new TypeError('Expected value to be a number');
 	}
 
 	if (!Number.isInteger(precision)) {
 		throw new TypeError('Expected precision to be an integer');
 	}
 
-	const isRoundingAndNegative = method === 'round' && input < 0;
+	const isRoundingAndNegative = method === 'round' && number < 0;
 	if (isRoundingAndNegative) {
-		input = Math.abs(input);
+		number = Math.abs(number);
 	}
 
-	let [number, exponent] = `${input}e`.split('e');
-	let ret = Math[method](`${number}e${Number(exponent) + precision}`);
+	let exponent;
+	[number, exponent] = `${number}e`.split('e');
+	let result = Math[method](`${number}e${Number(exponent) + precision}`);
 
-	[number, exponent] = `${ret}e`.split('e');
-	ret = Number(`${number}e${Number(exponent) - precision}`);
+	[number, exponent] = `${result}e`.split('e');
+	result = Number(`${number}e${Number(exponent) - precision}`);
 
 	if (isRoundingAndNegative) {
-		ret = -ret;
+		result = -result;
 	}
 
-	return ret;
+	return result;
 }
 
 module.exports = round.bind(null, 'round');

index.test-d.ts

@@ -0,0 +1,6 @@
+import {expectType} from 'tsd';
+import roundTo = require('.');
+
+expectType<number>(roundTo(1.234, 2));
+expectType<number>(roundTo.up(1.234, 2));
+expectType<number>(roundTo.down(1.234, 2));

package.json

@@ -10,13 +10,14 @@
 		"url": "sindresorhus.com"
 	},
 	"engines": {
-		"node": ">=6"
+		"node": ">=8"
 	},
 	"scripts": {
-		"test": "xo && ava"
+		"test": "xo && ava && tsd"
 	},
 	"files": [
-		"index.js"
+		"index.js",
+		"index.d.ts"
 	],
 	"keywords": [
 		"round",
@@ -30,7 +31,8 @@
 		"increment"
 	],
 	"devDependencies": {
-		"ava": "*",
-		"xo": "*"
+		"ava": "^1.4.1",
+		"tsd": "^0.7.2",
+		"xo": "^0.24.0"
 	}
 }

readme.md

@@ -25,7 +25,7 @@ roundTo.down(1.234, 2);
 //=> 1.23
 ```
 
-Numbers are rounded to a specific number of fractional digits. Specifying a negative precision will round to any number of places to the left of the decimal.
+Numbers are rounded to a specific number of fractional digits. Specifying a negative `precision` will round to any number of places to the left of the decimal.
 
 ```js
 roundTo(1234.56, -2);
@@ -34,27 +34,27 @@ roundTo(1234.56, -2);
 
 ## API
 
-### roundTo(value, precision)
+### roundTo(number, precision)
 
 Round the decimals with [`Math.round`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/round).
 
-### roundTo.up(value, precision)
+### roundTo.up(number, precision)
 
 Round up the decimals with [`Math.ceil`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/ceil).
 
-### roundTo.down(value, precision)
+### roundTo.down(number, precision)
 
 Round down the decimals with [`Math.floor`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor).
 
-#### value
+#### number
 
 Type: `number`
 
 Number to adjust.
 
 #### precision
 
-Type: `number` (integer)
+Type: `number` (Integer)
 
 Number of decimal places.
 

test.js

@@ -1,34 +1,34 @@
 import test from 'ava';
-import m from '.';
+import roundTo from '.';
 
 test('roundTo()', t => {
-	t.is(m(0.129, 3), 0.129);
-	t.is(m(0.129, 2), 0.13);
-	t.is(m(0.129, 1), 0.1);
-	t.is(m(1.005, 2), 1.01);
-	t.is(m(1.005, 0), 1);
-	t.is(m(111.1, -2), 100);
-	t.is(m(-0.375, 2), -0.38);
-	t.false(Number.isNaN(m(10000000000000, 8)));
-	t.is(m(0.37542323423423432432432432432, 8), 0.37542323);
+	t.is(roundTo(0.129, 3), 0.129);
+	t.is(roundTo(0.129, 2), 0.13);
+	t.is(roundTo(0.129, 1), 0.1);
+	t.is(roundTo(1.005, 2), 1.01);
+	t.is(roundTo(1.005, 0), 1);
+	t.is(roundTo(111.1, -2), 100);
+	t.is(roundTo(-0.375, 2), -0.38);
+	t.false(Number.isNaN(roundTo(10000000000000, 8)));
+	t.is(roundTo(0.37542323423423432432432432432, 8), 0.37542323);
 });
 
 test('roundTo.up()', t => {
-	t.is(m.up(0.111, 3), 0.111);
-	t.is(m.up(0.111, 2), 0.12);
-	t.is(m.up(0.111, 1), 0.2);
-	t.is(m.up(1.004, 2), 1.01);
-	t.is(m.up(1.111, 0), 2);
-	t.is(m.up(111.1, -2), 200);
-	t.is(m.up(-0.375, 2), -0.37);
+	t.is(roundTo.up(0.111, 3), 0.111);
+	t.is(roundTo.up(0.111, 2), 0.12);
+	t.is(roundTo.up(0.111, 1), 0.2);
+	t.is(roundTo.up(1.004, 2), 1.01);
+	t.is(roundTo.up(1.111, 0), 2);
+	t.is(roundTo.up(111.1, -2), 200);
+	t.is(roundTo.up(-0.375, 2), -0.37);
 });
 
 test('roundTo.down()', t => {
-	t.is(m.down(0.666, 3), 0.666);
-	t.is(m.down(0.666, 2), 0.66);
-	t.is(m.down(0.666, 1), 0.6);
-	t.is(m.down(1.006, 2), 1.00);
-	t.is(m.down(1.006, 0), 1);
-	t.is(m.down(111.6, -2), 100);
-	t.is(m.down(-0.375, 2), -0.38);
+	t.is(roundTo.down(0.666, 3), 0.666);
+	t.is(roundTo.down(0.666, 2), 0.66);
+	t.is(roundTo.down(0.666, 1), 0.6);
+	t.is(roundTo.down(1.006, 2), 1.0);
+	t.is(roundTo.down(1.006, 0), 1);
+	t.is(roundTo.down(111.6, -2), 100);
+	t.is(roundTo.down(-0.375, 2), -0.38);
 });