diff --git a/packages/core-api/src/lib/componentData.test.tsx b/packages/core-api/src/lib/componentData.test.tsx new file mode 100644 index 0000000000..6c4abda40f --- /dev/null +++ b/packages/core-api/src/lib/componentData.test.tsx @@ -0,0 +1,62 @@ +/* + * Copyright 2020 Spotify AB + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +import React from 'react'; +import { attachComponentData, getComponentData } from './componentData'; + +describe('elementData', () => { + it('should attach a single piece of data', () => { + const data = { foo: 'bar' }; + const Component = () => null; + attachComponentData(Component, 'my-data', data); + + const element = ; + expect(getComponentData(element, 'my-data')).toBe(data); + }); + + it('should attach several distinct pieces of data', () => { + const data1 = { foo: 'bar' }; + const data2 = { test: 'value' }; + const Component = () => null; + attachComponentData(Component, 'my-data', data1); + attachComponentData(Component, 'second', data2); + + const element = ; + expect(getComponentData(element, 'my-data')).toBe(data1); + expect(getComponentData(element, 'second')).toBe(data2); + }); + + it('returns undefined for missing data', () => { + const data = { foo: 'bar' }; + const Component1 = () => null; + const Component2 = () => null; + attachComponentData(Component2, 'my-data', data); + + const element1 = ; + const element2 = ; + expect(getComponentData(element1, 'missing')).toBeUndefined(); + expect(getComponentData(element2, 'missing')).toBeUndefined(); + }); + + it('should throw when attempting to overwrite data', () => { + const data = { foo: 'bar' }; + const MyComponent = () => null; + attachComponentData(MyComponent, 'my-data', data); + expect(() => attachComponentData(MyComponent, 'my-data', data)).toThrow( + 'Attempted to attach duplicate data "my-data" to component "MyComponent"', + ); + }); +}); diff --git a/packages/core-api/src/lib/componentData.tsx b/packages/core-api/src/lib/componentData.tsx new file mode 100644 index 0000000000..1f88356a48 --- /dev/null +++ b/packages/core-api/src/lib/componentData.tsx @@ -0,0 +1,69 @@ +/* + * Copyright 2020 Spotify AB + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +import { ComponentType, ReactNode } from 'react'; + +const DATA_KEY = Symbol('backstage-component-data'); + +type DataContainer = { + map: Map; +}; + +type ComponentWithData

= ComponentType

& { + [DATA_KEY]?: DataContainer; +}; + +type ReactNodeWithData = ReactNode & { + type?: { [DATA_KEY]?: DataContainer }; +}; + +export function attachComponentData

( + component: ComponentType

, + type: string, + data: unknown, +) { + const dataComponent = component as ComponentWithData

; + + let container = dataComponent[DATA_KEY]; + if (!container) { + container = dataComponent[DATA_KEY] = { map: new Map() }; + } + + if (container.map.has(type)) { + const name = component.displayName || component.name; + throw new Error( + `Attempted to attach duplicate data "${type}" to component "${name}"`, + ); + } + + container.map.set(type, data); +} + +export function getComponentData( + node: ReactNode, + type: string, +): T | undefined { + if (!node) { + return undefined; + } + + const container = (node as ReactNodeWithData).type?.[DATA_KEY]; + if (!container) { + return undefined; + } + + return container.map.get(type) as T | undefined; +}