| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | * |
| 7 | * @emails react-core |
| 8 | */ |
| 9 | |
| 10 | 'use strict'; |
| 11 | |
| 12 | let act; |
| 13 | |
| 14 | let React; |
| 15 | let ReactDOMClient; |
| 16 | let assertConsoleErrorDev; |
| 17 | let assertConsoleWarnDev; |
| 18 | |
| 19 | // NOTE: This module tests the old, "classic" JSX runtime, React.createElement. |
| 20 | // Do not use JSX syntax in this module; call React.createElement directly. |
| 21 | describe('ReactCreateElement', () => { |
| 22 | let ComponentClass; |
| 23 | |
| 24 | beforeEach(() => { |
| 25 | jest.resetModules(); |
| 26 | |
| 27 | ({ |
| 28 | act, |
| 29 | assertConsoleErrorDev, |
| 30 | assertConsoleWarnDev, |
| 31 | } = require('internal-test-utils')); |
| 32 | |
| 33 | React = require('react'); |
| 34 | ReactDOMClient = require('react-dom/client'); |
| 35 | ComponentClass = class extends React.Component { |
| 36 | render() { |
| 37 | return React.createElement('div'); |
| 38 | } |
| 39 | }; |
| 40 | }); |
| 41 | |
| 42 | it('returns a complete element according to spec', () => { |
| 43 | const element = React.createElement(ComponentClass); |
| 44 | expect(element.type).toBe(ComponentClass); |
| 45 | expect(element.key).toBe(null); |
| 46 | expect(element.ref).toBe(null); |
| 47 | if (__DEV__) { |
| 48 | expect(Object.isFrozen(element)).toBe(true); |
| 49 | expect(Object.isFrozen(element.props)).toBe(true); |
| 50 | } |
| 51 | expect(element.props).toEqual({}); |
| 52 | }); |
| 53 | |
| 54 | it('should warn when `key` is being accessed on composite element', async () => { |
| 55 | class Child extends React.Component { |
| 56 | render() { |
| 57 | return React.createElement('div', null, this.props.key); |
| 58 | } |
| 59 | } |
| 60 | class Parent extends React.Component { |
| 61 | render() { |
| 62 | return React.createElement( |
| 63 | 'div', |
| 64 | null, |
| 65 | React.createElement(Child, {key: '0'}), |
| 66 | React.createElement(Child, {key: '1'}), |
| 67 | React.createElement(Child, {key: '2'}), |
| 68 | ); |
| 69 | } |
| 70 | } |
| 71 | const root = ReactDOMClient.createRoot(document.createElement('div')); |
| 72 | await act(() => { |
| 73 | root.render(React.createElement(Parent)); |
| 74 | }); |
| 75 | assertConsoleErrorDev([ |
| 76 | 'Child: `key` is not a prop. Trying to access it will result ' + |
| 77 | 'in `undefined` being returned. If you need to access the same ' + |
| 78 | 'value within the child component, you should pass it as a different ' + |
| 79 | 'prop. (https://react.dev/link/special-props)\n' + |
| 80 | ' in Parent (at **)', |
| 81 | ]); |
| 82 | }); |
| 83 | |
| 84 | it('should warn when `key` is being accessed on a host element', () => { |
| 85 | const element = React.createElement('div', {key: '3'}); |
| 86 | void element.props.key; |
| 87 | assertConsoleErrorDev([ |
| 88 | 'div: `key` is not a prop. Trying to access it will result ' + |
| 89 | 'in `undefined` being returned. If you need to access the same ' + |
| 90 | 'value within the child component, you should pass it as a different ' + |
| 91 | 'prop. (https://react.dev/link/special-props)', |
| 92 | ]); |
| 93 | }); |
| 94 | |
| 95 | it('allows a string to be passed as the type', () => { |
| 96 | const element = React.createElement('div'); |
| 97 | expect(element.type).toBe('div'); |
| 98 | expect(element.key).toBe(null); |
| 99 | expect(element.ref).toBe(null); |
| 100 | if (__DEV__) { |
| 101 | expect(Object.isFrozen(element)).toBe(true); |
| 102 | expect(Object.isFrozen(element.props)).toBe(true); |
| 103 | } |
| 104 | expect(element.props).toEqual({}); |
| 105 | }); |
| 106 | |
| 107 | it('returns an immutable element', () => { |
| 108 | const element = React.createElement(ComponentClass); |
| 109 | if (__DEV__) { |
| 110 | expect(() => (element.type = 'div')).toThrow(); |
| 111 | } else { |
| 112 | expect(() => (element.type = 'div')).not.toThrow(); |
| 113 | } |
| 114 | }); |
| 115 | |
| 116 | it('does not reuse the original config object', () => { |
| 117 | const config = {foo: 1}; |
| 118 | const element = React.createElement(ComponentClass, config); |
| 119 | expect(element.props.foo).toBe(1); |
| 120 | config.foo = 2; |
| 121 | expect(element.props.foo).toBe(1); |
| 122 | }); |
| 123 | |
| 124 | it('does not fail if config has no prototype', () => { |
| 125 | const config = Object.create(null, {foo: {value: 1, enumerable: true}}); |
| 126 | const element = React.createElement(ComponentClass, config); |
| 127 | expect(element.props.foo).toBe(1); |
| 128 | }); |
| 129 | |
| 130 | it('extracts key from the rest of the props', () => { |
| 131 | const element = React.createElement(ComponentClass, { |
| 132 | key: '12', |
| 133 | foo: '56', |
| 134 | }); |
| 135 | expect(element.type).toBe(ComponentClass); |
| 136 | expect(element.key).toBe('12'); |
| 137 | const expectation = {foo: '56'}; |
| 138 | Object.freeze(expectation); |
| 139 | expect(element.props).toEqual(expectation); |
| 140 | }); |
| 141 | |
| 142 | it('does not extract ref from the rest of the props', () => { |
| 143 | const ref = React.createRef(); |
| 144 | const element = React.createElement(ComponentClass, { |
| 145 | key: '12', |
| 146 | ref: ref, |
| 147 | foo: '56', |
| 148 | }); |
| 149 | expect(element.type).toBe(ComponentClass); |
| 150 | expect(element.ref).toBe(ref); |
| 151 | assertConsoleErrorDev([ |
| 152 | 'Accessing element.ref was removed in React 19. ref is now a ' + |
| 153 | 'regular prop. It will be removed from the JSX Element ' + |
| 154 | 'type in a future release.', |
| 155 | ]); |
| 156 | const expectation = {foo: '56', ref}; |
| 157 | Object.freeze(expectation); |
| 158 | expect(element.props).toEqual(expectation); |
| 159 | }); |
| 160 | |
| 161 | it('extracts null key', () => { |
| 162 | const element = React.createElement(ComponentClass, { |
| 163 | key: null, |
| 164 | foo: '12', |
| 165 | }); |
| 166 | expect(element.type).toBe(ComponentClass); |
| 167 | expect(element.key).toBe('null'); |
| 168 | if (__DEV__) { |
| 169 | expect(Object.isFrozen(element)).toBe(true); |
| 170 | expect(Object.isFrozen(element.props)).toBe(true); |
| 171 | } |
| 172 | expect(element.props).toEqual({foo: '12'}); |
| 173 | }); |
| 174 | |
| 175 | it('ignores undefined key and ref', () => { |
| 176 | const props = { |
| 177 | foo: '56', |
| 178 | key: undefined, |
| 179 | ref: undefined, |
| 180 | }; |
| 181 | const element = React.createElement(ComponentClass, props); |
| 182 | expect(element.type).toBe(ComponentClass); |
| 183 | expect(element.key).toBe(null); |
| 184 | expect(element.ref).toBe(null); |
| 185 | if (__DEV__) { |
| 186 | expect(Object.isFrozen(element)).toBe(true); |
| 187 | expect(Object.isFrozen(element.props)).toBe(true); |
| 188 | } |
| 189 | expect(element.props).toEqual({foo: '56'}); |
| 190 | }); |
| 191 | |
| 192 | it('ignores key and ref warning getters', () => { |
| 193 | const elementA = React.createElement('div'); |
| 194 | const elementB = React.createElement('div', elementA.props); |
| 195 | expect(elementB.key).toBe(null); |
| 196 | expect(elementB.ref).toBe(null); |
| 197 | }); |
| 198 | |
| 199 | it('coerces the key to a string', () => { |
| 200 | const element = React.createElement(ComponentClass, { |
| 201 | key: 12, |
| 202 | foo: '56', |
| 203 | }); |
| 204 | expect(element.type).toBe(ComponentClass); |
| 205 | expect(element.key).toBe('12'); |
| 206 | expect(element.ref).toBe(null); |
| 207 | if (__DEV__) { |
| 208 | expect(Object.isFrozen(element)).toBe(true); |
| 209 | expect(Object.isFrozen(element.props)).toBe(true); |
| 210 | } |
| 211 | expect(element.props).toEqual({foo: '56'}); |
| 212 | }); |
| 213 | |
| 214 | it('preserves the owner on the element', async () => { |
| 215 | let element; |
| 216 | let instance; |
| 217 | |
| 218 | class Wrapper extends React.Component { |
| 219 | componentDidMount() { |
| 220 | instance = this; |
| 221 | } |
| 222 | render() { |
| 223 | element = React.createElement(ComponentClass); |
| 224 | return element; |
| 225 | } |
| 226 | } |
| 227 | const root = ReactDOMClient.createRoot(document.createElement('div')); |
| 228 | await act(() => root.render(React.createElement(Wrapper))); |
| 229 | if (__DEV__) { |
| 230 | expect(element._owner.stateNode).toBe(instance); |
| 231 | } else { |
| 232 | expect('_owner' in element).toBe(false); |
| 233 | } |
| 234 | }); |
| 235 | |
| 236 | it('merges an additional argument onto the children prop', () => { |
| 237 | const a = 1; |
| 238 | const element = React.createElement( |
| 239 | ComponentClass, |
| 240 | { |
| 241 | children: 'text', |
| 242 | }, |
| 243 | a, |
| 244 | ); |
| 245 | expect(element.props.children).toBe(a); |
| 246 | }); |
| 247 | |
| 248 | it('does not override children if no rest args are provided', () => { |
| 249 | const element = React.createElement(ComponentClass, { |
| 250 | children: 'text', |
| 251 | }); |
| 252 | expect(element.props.children).toBe('text'); |
| 253 | }); |
| 254 | |
| 255 | it('overrides children if null is provided as an argument', () => { |
| 256 | const element = React.createElement( |
| 257 | ComponentClass, |
| 258 | { |
| 259 | children: 'text', |
| 260 | }, |
| 261 | null, |
| 262 | ); |
| 263 | expect(element.props.children).toBe(null); |
| 264 | }); |
| 265 | |
| 266 | it('merges rest arguments onto the children prop in an array', () => { |
| 267 | const a = 1; |
| 268 | const b = 2; |
| 269 | const c = 3; |
| 270 | const element = React.createElement(ComponentClass, null, a, b, c); |
| 271 | expect(element.props.children).toEqual([1, 2, 3]); |
| 272 | }); |
| 273 | |
| 274 | it('allows static methods to be called using the type property', () => { |
| 275 | class StaticMethodComponentClass extends React.Component { |
| 276 | render() { |
| 277 | return React.createElement('div'); |
| 278 | } |
| 279 | } |
| 280 | StaticMethodComponentClass.someStaticMethod = () => 'someReturnValue'; |
| 281 | |
| 282 | const element = React.createElement(StaticMethodComponentClass); |
| 283 | expect(element.type.someStaticMethod()).toBe('someReturnValue'); |
| 284 | }); |
| 285 | |
| 286 | it('is indistinguishable from a plain object', () => { |
| 287 | const element = React.createElement('div', {className: 'foo'}); |
| 288 | const object = {}; |
| 289 | expect(element.constructor).toBe(object.constructor); |
| 290 | }); |
| 291 | |
| 292 | it('should use default prop value when removing a prop', async () => { |
| 293 | class Component extends React.Component { |
| 294 | render() { |
| 295 | return React.createElement('span'); |
| 296 | } |
| 297 | } |
| 298 | Component.defaultProps = {fruit: 'persimmon'}; |
| 299 | |
| 300 | const container = document.createElement('div'); |
| 301 | const root = ReactDOMClient.createRoot(container); |
| 302 | |
| 303 | const ref = React.createRef(); |
| 304 | await act(() => { |
| 305 | root.render(React.createElement(Component, {ref, fruit: 'mango'})); |
| 306 | }); |
| 307 | const instance = ref.current; |
| 308 | expect(instance.props.fruit).toBe('mango'); |
| 309 | |
| 310 | await act(() => { |
| 311 | root.render(React.createElement(Component)); |
| 312 | }); |
| 313 | expect(instance.props.fruit).toBe('persimmon'); |
| 314 | }); |
| 315 | |
| 316 | it('should normalize props with default values', async () => { |
| 317 | let instance; |
| 318 | class Component extends React.Component { |
| 319 | componentDidMount() { |
| 320 | instance = this; |
| 321 | } |
| 322 | render() { |
| 323 | return React.createElement('span', null, this.props.prop); |
| 324 | } |
| 325 | } |
| 326 | Component.defaultProps = {prop: 'testKey'}; |
| 327 | |
| 328 | const root = ReactDOMClient.createRoot(document.createElement('div')); |
| 329 | await act(() => { |
| 330 | root.render(React.createElement(Component)); |
| 331 | }); |
| 332 | expect(instance.props.prop).toBe('testKey'); |
| 333 | |
| 334 | await act(() => { |
| 335 | root.render(React.createElement(Component, {prop: null})); |
| 336 | }); |
| 337 | expect(instance.props.prop).toBe(null); |
| 338 | }); |
| 339 | |
| 340 | it('throws when changing a prop (in dev) after element creation', async () => { |
| 341 | class Outer extends React.Component { |
| 342 | render() { |
| 343 | const el = React.createElement('div', {className: 'moo'}); |
| 344 | |
| 345 | if (__DEV__) { |
| 346 | expect(function () { |
| 347 | el.props.className = 'quack'; |
| 348 | }).toThrow(); |
| 349 | expect(el.props.className).toBe('moo'); |
| 350 | } else { |
| 351 | el.props.className = 'quack'; |
| 352 | expect(el.props.className).toBe('quack'); |
| 353 | } |
| 354 | |
| 355 | return el; |
| 356 | } |
| 357 | } |
| 358 | |
| 359 | const container = document.createElement('div'); |
| 360 | const root = ReactDOMClient.createRoot(container); |
| 361 | |
| 362 | await act(() => { |
| 363 | root.render(React.createElement(Outer, {color: 'orange'})); |
| 364 | }); |
| 365 | if (__DEV__) { |
| 366 | expect(container.firstChild.className).toBe('moo'); |
| 367 | } else { |
| 368 | expect(container.firstChild.className).toBe('quack'); |
| 369 | } |
| 370 | }); |
| 371 | |
| 372 | it('throws when adding a prop (in dev) after element creation', async () => { |
| 373 | const container = document.createElement('div'); |
| 374 | class Outer extends React.Component { |
| 375 | render() { |
| 376 | const el = React.createElement('div', null, this.props.sound); |
| 377 | |
| 378 | if (__DEV__) { |
| 379 | expect(function () { |
| 380 | el.props.className = 'quack'; |
| 381 | }).toThrow(); |
| 382 | expect(el.props.className).toBe(undefined); |
| 383 | } else { |
| 384 | el.props.className = 'quack'; |
| 385 | expect(el.props.className).toBe('quack'); |
| 386 | } |
| 387 | |
| 388 | return el; |
| 389 | } |
| 390 | } |
| 391 | Outer.defaultProps = {sound: 'meow'}; |
| 392 | const root = ReactDOMClient.createRoot(container); |
| 393 | await act(() => { |
| 394 | root.render(React.createElement(Outer)); |
| 395 | }); |
| 396 | expect(container.firstChild.textContent).toBe('meow'); |
| 397 | if (__DEV__) { |
| 398 | expect(container.firstChild.className).toBe(''); |
| 399 | } else { |
| 400 | expect(container.firstChild.className).toBe('quack'); |
| 401 | } |
| 402 | }); |
| 403 | |
| 404 | it('does not warn for NaN props', async () => { |
| 405 | let test; |
| 406 | class Test extends React.Component { |
| 407 | componentDidMount() { |
| 408 | test = this; |
| 409 | } |
| 410 | render() { |
| 411 | return React.createElement('div'); |
| 412 | } |
| 413 | } |
| 414 | const root = ReactDOMClient.createRoot(document.createElement('div')); |
| 415 | await act(() => { |
| 416 | root.render(React.createElement(Test, {value: +undefined})); |
| 417 | }); |
| 418 | expect(test.props.value).toBeNaN(); |
| 419 | }); |
| 420 | |
| 421 | it('warns if outdated JSX transform is detected', async () => { |
| 422 | // Warns if __self is detected, because that's only passed by a compiler |
| 423 | React.createElement('div', {className: 'foo', __self: this}); |
| 424 | assertConsoleWarnDev([ |
| 425 | 'Your app (or one of its dependencies) is using an outdated JSX ' + |
| 426 | 'transform. Update to the modern JSX transform for ' + |
| 427 | 'faster performance: https://react.dev/link/new-jsx-transform', |
| 428 | ]); |
| 429 | |
| 430 | // Only warns the first time. Subsequent elements don't warn. |
| 431 | React.createElement('div', {className: 'foo', __self: this}); |
| 432 | }); |
| 433 | |
| 434 | it('do not warn about outdated JSX transform if `key` is present', () => { |
| 435 | // When a static "key" prop is defined _after_ a spread, the modern JSX |
| 436 | // transform outputs `createElement` instead of `jsx`. (This is because with |
| 437 | // `jsx`, a spread key always takes precedence over a static key, regardless |
| 438 | // of the order, whereas `createElement` respects the order.) |
| 439 | // |
| 440 | // To avoid a false positive warning, we skip the warning whenever a `key` |
| 441 | // prop is present. |
| 442 | React.createElement('div', {key: 'foo', __self: this}); |
| 443 | }); |
| 444 | }); |