Move math stuff to ts (#35)

* Move modulo to ts

* Move subtract to ts

* Move reduce to ts

* Move sum to ts

* Move negate to ts

* Move multiply to ts

* Move median to ts

* Migrate tests to ts

* Move mean to ts

* Move slice to ts

* Fix type errors

.changeset/calm-vans-shop.md

@@ -0,0 +1,5 @@
+---
+'frans': minor
+---
+
+Move reduce to ts

.changeset/chatty-bags-fail.md

@@ -0,0 +1,5 @@
+---
+'frans': minor
+---
+
+Move negate to ts

.changeset/cuddly-steaks-live.md

@@ -0,0 +1,5 @@
+---
+'frans': minor
+---
+
+Move modulo to ts

.changeset/eleven-days-mate.md

@@ -0,0 +1,5 @@
+---
+'frans': minor
+---
+
+Move median to ts

.changeset/famous-deers-study.md

@@ -0,0 +1,5 @@
+---
+'frans': minor
+---
+
+Move sum to ts

.changeset/serious-donuts-complain.md

@@ -0,0 +1,5 @@
+---
+'frans': minor
+---
+
+Move slice to ts

.changeset/silent-ways-divide.md

@@ -0,0 +1,5 @@
+---
+'frans': minor
+---
+
+Move multiply to ts

.changeset/smart-crabs-accept.md

@@ -0,0 +1,5 @@
+---
+'frans': patch
+---
+
+Move mean to ts

.changeset/warm-pugs-report.md

@@ -0,0 +1,5 @@
+---
+'frans': minor
+---
+
+Move subtract to ts

src/__tests__/mean.js → src/__tests__/mean.ts

@@ -11,12 +11,4 @@ describe('Core.mean', () => {
   test('returns NaN for empty list', () => {
     expect(mean([])).toBe(NaN);
   });
-
-  test('handles array-like object', () => {
-    function getArgs() {
-      return arguments; // eslint-disable-line prefer-rest-params
-    }
-
-    expect(mean(getArgs(1, 2, 3))).toBe(2);
-  });
 });

src/__tests__/median.js → src/__tests__/median.ts

@@ -16,12 +16,4 @@ describe('Core.median', () => {
   test('returns NaN for an empty list', () => {
     expect(median([])).toBe(NaN);
   });
-
-  test('handles array-like object', () => {
-    function getArgs() {
-      return arguments; // eslint-disable-line prefer-rest-params
-    }
-
-    expect(median(getArgs(1, 2, 3))).toBe(2);
-  });
 });

src/__tests__/reduce.js → src/__tests__/reduce.ts

@@ -1,14 +1,15 @@
 import { reduce } from '../reduce';
 
 describe('Core.reduce', () => {
-  const add = (x, y) => x + y;
-  const mult = (x, y) => x * y;
-  const append = (arr, e) => arr.concat(e);
+  const add = (x: number, y: number) => x + y;
+  const mult = (x: number, y: number) => x * y;
+  const concat = <T>(arr: T[], e: T) => arr.concat(e);
 
   test('folds simple fns over arrays with the supplied accumulator', () => {
     expect(reduce(add, 0, [1, 2, 3, 4])).toBe(10);
     expect(reduce(mult, 1, [1, 2, 3, 4])).toBe(24);
-    expect(reduce(append, [], [1, 2, 3, 4])).toEqual([1, 2, 3, 4]);
+
+    expect(reduce<number>(concat, [], [1, 2, 3, 4])).toEqual([1, 2, 3, 4]);
   });
 
   test('returns the accumulator for an empty array', () => {

src/__tests__/slice.js → src/__tests__/slice.ts

@@ -7,7 +7,7 @@ describe('Core.slice', () => {
   });
 
   test('handles array-like object', () => {
-    const args = (function getArgs() {
+    const args = (function getArgs(..._: any[]) {
       return arguments; // eslint-disable-line prefer-rest-params
     })(1, 2, 3, 4, 5);
 

src/adjust.ts

@@ -6,7 +6,7 @@ import { isArray } from './isArray';
 export function adjust<T, R>(
   i: number,
   fn: (input: T) => R,
-  list: T[] | ArrayLike<T>,
+  list: ArrayLike<T>,
 ): (T | R)[] {
   const arrLength = length(list);
   if (i >= arrLength || i < -arrLength) {

src/internal/values.ts

@@ -4,7 +4,9 @@ import { append } from '../append';
 import { prop } from '../prop';
 
 export const values = <V = unknown>(obj: Record<string, V>): V[] => {
-  const props = keys(obj);
+  const props = keys(obj).filter(
+    (key): key is string => typeof key === 'string',
+  );
   return reduce(
     (acc: V[], key: string) => append(prop(key, obj), acc),
     [],

src/mean.js → src/mean.ts

@@ -2,7 +2,7 @@ import { sum } from './sum';
 import { divide } from './divide';
 import { length } from './length';
 
-const mean = (list) => {
+const mean = (list: number[]): number => {
   const l = length(list);
   const s = sum(list);
   return divide(s, l);

src/median.js → src/median.ts

@@ -7,7 +7,7 @@ import { nth } from './nth';
 import { slice } from './slice';
 import { mean } from './mean';
 
-const median = (list) => {
+export function median(list: number[]): number {
   const sorted = sort(subtract, list);
   const l = length(sorted);
   const half = divide(l, 2);
@@ -16,6 +16,4 @@ const median = (list) => {
 
   const sub = slice(half - 1, half + 1, sorted);
   return mean(sub);
-};
-
-export { median };
+}

src/modulo.ts

@@ -0,0 +1,3 @@
+export function modulo(a: number, b: number) {
+  return a % b;
+}

src/multiply.ts

@@ -0,0 +1,3 @@
+export function multiply(a: number, b: number) {
+  return a * b;
+}

src/negate.ts

@@ -0,0 +1,3 @@
+export function negate(n: number) {
+  return -n;
+}

src/reduce.js → src/reduce.ts

@@ -1,6 +1,10 @@
 import { length } from './length';
 
-const reduce = (fn, init, arr) => {
+export function reduce<I, T = I[]>(
+  fn: (acc: T, item: I) => T,
+  init: T,
+  arr: I[],
+): T {
   let idx = 0;
   let accumulator = init;
   const len = length(arr);
@@ -11,6 +15,4 @@ const reduce = (fn, init, arr) => {
   }
 
   return accumulator;
-};
-
-export { reduce };
+}

src/slice.ts

@@ -0,0 +1,14 @@
+import { isString } from './isString';
+
+export function slice(start: number, end: number, arr: string): string;
+export function slice<T>(start: number, end: number, arr: ArrayLike<T>): T[];
+export function slice<T>(
+  start: number,
+  end: number,
+  arr: ArrayLike<T> | string,
+): T[] | string {
+  if (isString(arr)) {
+    return String.prototype.slice.call(arr, start, end);
+  }
+  return Array.prototype.slice.call(arr, start, end);
+}

src/subtract.ts

@@ -0,0 +1,3 @@
+export function subtract(a: number, b: number) {
+  return a - b;
+}

src/sum.ts

@@ -0,0 +1,6 @@
+import { add } from './add';
+import { reduce } from './reduce';
+
+export function sum(list: number[]) {
+  return reduce(add, 0, list);
+}

tsconfig.json

@@ -3,6 +3,7 @@
     "target": "es5",
     "lib": ["dom", "dom.iterable", "esnext"],
     "allowJs": true,
+    "checkJs": false,
     "skipLibCheck": true,
     "esModuleInterop": true,
     "allowSyntheticDefaultImports": true,