fix: use same ignored value rules as SX

see https://reactjs.org/docs/jsx-in-depth.html#booleans-null-and-undefined-are-ignored

Author: sastan

.size-snapshot.json

@@ -1,13 +1,13 @@
 {
   "dist/react-render-callback.umd.js": {
-    "bundled": 4399,
-    "minified": 1771,
-    "gzipped": 759
+    "bundled": 4334,
+    "minified": 1702,
+    "gzipped": 746
   },
   "dist/react-render-callback.esm.js": {
-    "bundled": 2730,
-    "minified": 1567,
-    "gzipped": 649,
+    "bundled": 2665,
+    "minified": 1526,
+    "gzipped": 638,
     "treeshaked": {
       "rollup": {
         "code": 289,
@@ -19,13 +19,13 @@
     }
   },
   "dist/react-render-callback.cjs.js": {
-    "bundled": 2903,
-    "minified": 1695,
-    "gzipped": 686
+    "bundled": 2838,
+    "minified": 1654,
+    "gzipped": 677
   },
   "dist/react-render-callback.umd.min.js": {
-    "bundled": 4432,
-    "minified": 1757,
-    "gzipped": 749
+    "bundled": 4367,
+    "minified": 1688,
+    "gzipped": 737
   }
 }

README.md

@@ -60,7 +60,8 @@ It can render the following types:
 - [Elements](https://reactjs.org/docs/glossary.html#elements)
   with [optional support](#use-optionscloneelement) for [cloning][clone-element] to merge props
 - primitives like strings, numbers, arrays, ...
-- `false`, `null`, `undefined`, `NaN` and an empty string are coerced to `null`
+- `false`, `null`, `undefined` and `true` are returned as `null`
+  just like in [JSX](https://reactjs.org/docs/jsx-in-depth.html#booleans-null-and-undefined-are-ignored)
 
 View an example in [codesandbox.io](https://codesandbox.io/s/48k5p1r764?module=%2FApp.js).
 
@@ -146,7 +147,8 @@ const render = require('react-render-callback')
 
 **returns**
 
-- `null` for `false`, `null`, `undefined`, `NaN` and an empty string
+- `false`, `null`, `undefined` and `true` are returned as `null`
+  just like in [JSX](https://reactjs.org/docs/jsx-in-depth.html#booleans-null-and-undefined-are-ignored)
 - the value as is for all other values
 
 #### `createRender([ renderable [, options ] ])`

src/createRender.js

@@ -3,7 +3,7 @@ import {isValidElement, createElement, cloneElement} from 'react'
 import isPlainObject from 'is-plain-object'
 
 import constant from './internal/constant'
-import falsyToNull from './internal/falsyToNull'
+import ignoredValuesToNull from './internal/ignoredValuesToNull'
 import isReactComponent from './internal/isReactComponent'
 
 export default (renderable, options) => {
@@ -14,15 +14,11 @@ export default (renderable, options) => {
   if (typeof renderable === 'function') {
     return (...args) => {
       const element =
-        args.length === 1 && isPlainObject(args[0])
-          ? renderable(
-              renderable.defaultProps
-                ? {...renderable.defaultProps, ...args[0]}
-                : args[0],
-            )
+        renderable.defaultProps && args.length === 1 && isPlainObject(args[0])
+          ? renderable({...renderable.defaultProps, ...args[0]})
           : renderable(...args)
 
-      return falsyToNull(element)
+      return ignoredValuesToNull(element)
     }
   }
 
@@ -31,5 +27,5 @@ export default (renderable, options) => {
   }
 
   // must be something else
-  return constant(falsyToNull(renderable))
+  return constant(ignoredValuesToNull(renderable))
 }

src/internal/falsyToNull.js

@@ -0,0 +1,3 @@
+import isIgnored from './isIgnored'
+
+export default value => (isIgnored(value) ? null : value)

src/internal/ignoredValuesToNull.js

@@ -0,0 +1 @@
+export default value => value == null || value === false || value === true

src/internal/isFalsy.js

@@ -55,15 +55,15 @@ describe('render([renderable[, props]])', () => {
   })
 
   describe('should return null for', () => {
-    ;[false, null, undefined, NaN, ''].forEach(value => {
+    ;[false, null, undefined, true].forEach(value => {
       it(`${value}`, () => {
         expect(render(value)).toBeNull()
       })
     })
   })
 
   describe('should return value', () => {
-    ;[true, 0].forEach(value => {
+    ;['', 0, NaN].forEach(value => {
       it(`${value}`, () => {
         expect(render(value)).toBe(value)
       })
@@ -208,15 +208,15 @@ Object {
     const SFC = ({value}) => value
 
     describe('return null for', () => {
-      ;[false, null, undefined, NaN, ''].forEach(value => {
+      ;[false, null, undefined, true].forEach(value => {
         it(`${value}`, () => {
           expect(render(SFC, {value})).toBeNull()
         })
       })
     })
 
     describe('return value', () => {
-      ;[true, 0].forEach(value => {
+      ;['', 0, NaN].forEach(value => {
         it(`${value}`, () => {
           expect(render(SFC, {value})).toBe(value)
         })