✨ Add ifElseFn and change ifElse function

api.ts

@@ -201,11 +201,10 @@ const api: Api = {
     lodash: 'findIndex',
     fonction: undefined
   },
-
-  ifElse: {
+  ifElse: {},
+  ifElseFn: {
     ramda: 'ifElse',
-    rambda: 'ifElse',
-    fonction: undefined
+    rambda: 'ifElse'
   },
   includes: {
     ramda: 'includes',

mod.ts

@@ -20,6 +20,7 @@ export { hasPath } from './src/hasPath.ts'
 export { head } from './src/head.ts'
 export { identity } from './src/identity.ts'
 export { ifElse } from './src/ifElse.ts'
+export { ifElseFn } from './src/ifElseFn.ts'
 export { inc } from './src/inc.ts'
 export { isArray } from './src/isArray.ts'
 export { isBigint } from './src/isBigint.ts'

src/ifElse.ts

@@ -1,40 +1,36 @@
 // Copyright 2021-present the Fonction authors. All rights reserved. MIT license.
-import { isFunction } from './isFunction.ts'
-
+import { NN } from './NN.ts'
+import { Falsy } from './types/index.ts'
 /**
- * Creates a function that will process either the `onTrue` or the `onFalse` function depending upon the result of the condition predicate.
+ * Return the `onTrue` or the `onFalse` value depending upon the result of the condition `val`.
  *
- * @param condition - A predicate function
- * @param onTrue - Any value or A function to invoke when the `condition` evaluates to a truthy value
- * @param onFalse - Any value or A function to invoke when the `condition` evaluates to a falsy value
- * @returns A new function that will process either the `onTrue` or the `onFalse` function depending upon the result of the `condition` predicate
+ * @param val - A predicate value
+ * @param onTrue - The `val` evaluates to a truthy value
+ * @param onFalse - The `val` evaluates to a falsy value
+ * @returns The result of `!!val` ? `onTrue` : `onFalse`
  *
  * @example
  * ```ts
- * ifElse((x: number) => x > 10, 'big', 'small')(20) // 'big'
- * const fn = ifElse((x: number) => x > 10, (x) => x + 1, (x) => x - 1)
- * fn(11) // 12
- * fn(9) // 8
+ * ifElse(true, 1, 0) // 1
+ * ifElse(false, 1, 0) // 0
+ * ifElse(undefined, 1, 0) // 0
  * ```
  *
  * @category `Logic`
  *
+ * @see Related to {@link ifElseFn}
+ *
  * @beta
  */
-const ifElse = <V, R extends boolean, T, F>(
-  condition: (val: V) => R,
-  onTrue: T | ((val: V) => T),
-  onFalse: F | ((val: V) => F)
-) => (val: V): R extends true ? T : R extends false ? F : T | F => {
-  if (condition(val)) {
-    return isFunction(onTrue)
-      ? (onTrue as (val: V) => T)(val)
-      : ((onTrue as T) as any)
-  } else {
-    return isFunction(onFalse)
-      ? (onFalse as (val: V) => F)(val)
-      : ((onFalse as F) as any)
-  }
-}
+const ifElse = <V, T, F>(
+  val: V,
+  onTrue: T,
+  onFalse: F
+): V extends Falsy ? F : V extends true ? T : T | F =>
+  (NN(val) ? onTrue : onFalse) as V extends Falsy
+    ? F
+    : V extends true
+    ? T
+    : T | F
 
 export { ifElse }

src/ifElseFn.ts

@@ -0,0 +1,42 @@
+// Copyright 2021-present the Fonction authors. All rights reserved. MIT license.
+import { isFunction } from './isFunction.ts'
+import { Falsy } from './types/index.ts'
+/**
+ * Creates a function that will process either the `onTrue` or the `onFalse` function depending upon the result of the condition predicate.
+ *
+ * @param condition - A predicate function
+ * @param onTrue - Any value or A function to invoke when the `condition` evaluates to a truthy value
+ * @param onFalse - Any value or A function to invoke when the `condition` evaluates to a falsy value
+ * @returns A new function that will process either the `onTrue` or the `onFalse` function depending upon the result of the `condition` predicate
+ *
+ * @example
+ * ```ts
+ * ifElseFn((x: number) => x > 10, 'big', 'small')(20) // 'big'
+ * const fn = ifElseFn((x: number) => x > 10, (x) => x + 1, (x) => x - 1)
+ * fn(11) // 12
+ * fn(9) // 8
+ * ```
+ *
+ * @category `Logic`
+ *
+ * @see Related to {@link ifElse}
+ *
+ * @beta
+ */
+const ifElseFn = <V, R, T, F>(
+  condition: (val: V) => R,
+  onTrue: T | ((val: V) => T),
+  onFalse: F | ((val: V) => F)
+) => (val: V): R extends true ? T : R extends Falsy ? F : T | F => {
+  if (condition(val)) {
+    return isFunction(onTrue)
+      ? (onTrue as (val: V) => T)(val)
+      : ((onTrue as T) as any)
+  } else {
+    return isFunction(onFalse)
+      ? (onFalse as (val: V) => F)(val)
+      : ((onFalse as F) as any)
+  }
+}
+
+export { ifElseFn }

test/ifElse.test.ts

@@ -4,48 +4,31 @@ import { ifElse } from '../src/ifElse.ts'
 import { assertEqual } from './asserts.ts'
 
 Deno.test('ifElse', () => {
-  const table: [
-    (val: any) => boolean,
-    ((val: unknown) => boolean) | unknown,
-    ((val: unknown) => boolean) | unknown,
-    unknown,
-    unknown
-  ][] = [
-    [() => true, 1, 0, 1, 1],
-    [() => false, 1, 0, 1, 0],
-    [(x: unknown) => !!x, 1, 0, 1, 1],
-    [(x: unknown) => !!x, 1, 0, 0, 0],
-    [(x: unknown) => !!x, () => 2, 0, 1, 2],
-    [(x: unknown) => !!x, () => 2, () => 3, 0, 3],
-    [(x: unknown) => !!x, (x: number) => x + 1, () => 3, 1, 2],
-    [(x: unknown) => !!x, (x: number) => x + 1, (x: number) => x - 1, 0, -1]
+  const table: [unknown, unknown, unknown, unknown][] = [
+    [true, 1, 0, 1],
+    [{}, 1, 0, 1],
+    [[], 1, 0, 1],
+    ['hello', 1, 0, 1],
+    [false, 1, 0, 0],
+    ['', 1, 0, 0],
+    [NaN, 1, 0, 0],
+    [undefined, 1, 0, 0],
+    [null, 1, 0, 0],
+    [0, 1, 0, 0]
   ]
 
-  table.forEach(([condition, onTrue, onFalse, val, expected]) => {
+  table.forEach(([val, onTrue, onFalse, expected]) => {
     assertEquals(
-      ifElse(condition, onTrue, onFalse)(val),
+      ifElse(val, onTrue, onFalse),
       expected,
-      `ifElse(${condition}, ${onTrue}, ${onFalse})(${val}) -> ${expected}`
+      `ifElse(${val}, ${onTrue}, ${onFalse}) -> ${expected}`
     )
   })
 
-  assertEqual<number>(ifElse(() => true as const, 1, 0)(1))
-  assertEqual<1>(ifElse(() => true as const, 1 as const, 0 as const)(1))
-  assertEqual<0>(ifElse(() => false as const, 1 as const, 0 as const)(1))
-  assertEqual<1 | 0>(ifElse(() => true as boolean, 1 as const, 0 as const)(1))
-  assertEqual<1 | 0>(ifElse((x: string) => !!x, 1 as const, 0 as const)(''))
-  assertEqual<number>(
-    ifElse(
-      (x: number) => !!x,
-      (x: number) => x + 1,
-      0 as const
-    )(0)
-  )
-  assertEqual<number>(
-    ifElse(
-      (x: number) => !!x,
-      (x: number) => x + 1,
-      (x: number) => x - 1
-    )(0)
-  )
+  assertEqual<number>(ifElse(true, 1, 0))
+  assertEqual<number>(ifElse(true as const, 1, 0))
+  assertEqual<1>(ifElse(true as const, 1 as const, 0))
+  assertEqual<0>(ifElse(false as const, 1 as const, 0 as const))
+  assertEqual<1 | ''>(ifElse(false, 1 as const, '' as const))
+  assertEqual<1 | ''>(ifElse({}, 1 as const, '' as const))
 })

test/ifElseFn.test.ts

@@ -0,0 +1,55 @@
+// Copyright 2021-present the Fonction authors. All rights reserved. MIT license.
+import { assertEquals } from '../deps.ts'
+import { ifElseFn } from '../src/ifElseFn.ts'
+import { assertEqual } from './asserts.ts'
+
+Deno.test('ifElseFn', () => {
+  const table: [
+    (val: any) => boolean,
+    ((val: unknown) => boolean) | unknown,
+    ((val: unknown) => boolean) | unknown,
+    unknown,
+    unknown
+  ][] = [
+    [() => true, 1, 0, 1, 1],
+    [() => false, 1, 0, 1, 0],
+    [(x: unknown) => !!x, 1, 0, 1, 1],
+    [(x: unknown) => !!x, 1, 0, 0, 0],
+    [(x: unknown) => !!x, () => 2, 0, 1, 2],
+    [(x: unknown) => !!x, () => 2, () => 3, 0, 3],
+    [(x: unknown) => !!x, (x: number) => x + 1, () => 3, 1, 2],
+    [(x: unknown) => !!x, (x: number) => x + 1, (x: number) => x - 1, 0, -1]
+  ]
+
+  table.forEach(([condition, onTrue, onFalse, val, expected]) => {
+    assertEquals(
+      ifElseFn(condition, onTrue, onFalse)(val),
+      expected,
+      `ifElseFn(${condition}, ${onTrue}, ${onFalse})(${val}) -> ${expected}`
+    )
+  })
+
+  assertEqual<number>(ifElseFn(() => true as const, 1, 0)(1))
+  assertEqual<1>(ifElseFn(() => true as const, 1 as const, 0 as const)(1))
+  assertEqual<0>(ifElseFn(() => false as const, 1 as const, 0 as const)(1))
+  assertEqual<0>(ifElseFn(() => '' as const, 1 as const, 0 as const)(1))
+  assertEqual<0>(ifElseFn(() => undefined, 1 as const, 0 as const)(1))
+  assertEqual<0>(ifElseFn(() => null, 1 as const, 0 as const)(1))
+  assertEqual<0>(ifElseFn(() => 0 as const, 1 as const, 0 as const)(1))
+  assertEqual<1 | 0>(ifElseFn(() => true as boolean, 1 as const, 0 as const)(1))
+  assertEqual<1 | 0>(ifElseFn((x: string) => !!x, 1 as const, 0 as const)(''))
+  assertEqual<number>(
+    ifElseFn(
+      (x: number) => !!x,
+      (x: number) => x + 1,
+      0 as const
+    )(0)
+  )
+  assertEqual<number>(
+    ifElseFn(
+      (x: number) => !!x,
+      (x: number) => x + 1,
+      (x: number) => x - 1
+    )(0)
+  )
+})