protocol/packages/website/ts/lazy_component.tsx
Xianny 7423028fea
Replace lodash with built-ins where possible to reduce bundle size (#1766)
* add tslint rule to disallow lodash.isUndefined

* add tslint rule to disallow lodash.isNull

* apply fixes
2019-04-10 09:36:32 -07:00

67 lines
2.5 KiB
TypeScript

import * as _ from 'lodash';
import * as React from 'react';
interface LazyComponentProps {
reactComponentPromise: Promise<React.ComponentClass<any>>;
reactComponentProps: any;
}
interface LazyComponentState {
component?: React.ComponentClass<any>;
}
/**
* This component is used for rendering components that are lazily loaded from other chunks.
* Source: https://reacttraining.com/react-router/web/guides/code-splitting
*/
export class LazyComponent extends React.Component<LazyComponentProps, LazyComponentState> {
constructor(props: LazyComponentProps) {
super(props);
this.state = {
component: undefined,
};
}
public componentWillMount(): void {
// tslint:disable-next-line:no-floating-promises
this._loadComponentFireAndForgetAsync(this.props);
}
public componentWillReceiveProps(nextProps: LazyComponentProps): void {
if (nextProps.reactComponentPromise !== this.props.reactComponentPromise) {
// tslint:disable-next-line:no-floating-promises
this._loadComponentFireAndForgetAsync(nextProps);
}
}
public render(): React.ReactNode {
return this.state.component === undefined
? null
: React.createElement(this.state.component, this.props.reactComponentProps);
}
private async _loadComponentFireAndForgetAsync(props: LazyComponentProps): Promise<void> {
const component = await props.reactComponentPromise;
this.setState({
component,
});
}
}
/**
* [createLazyComponent description]
* @param componentName name of exported component
* @param lazyImport lambda returning module promise
* we pass a lambda because we only want to require a module if it's used
* @example `const LazyPortal = createLazyComponent('Portal', () => import<any>('ts/containers/portal'));``
*/
export const createLazyComponent = (componentName: string, lazyImport: () => Promise<any>) => {
return (props: any) => {
const reactComponentPromise = (async (): Promise<React.ComponentClass<any>> => {
const mod = await lazyImport();
const component = mod[componentName];
if (component === undefined) {
throw new Error(`Did not find exported component: ${componentName}`);
}
return component;
})();
return <LazyComponent reactComponentPromise={reactComponentPromise} reactComponentProps={props} />;
};
};