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Omlet vs. React Scanner
Before Omlet was around, the most common way developers would analyze component usage was to use React Scanner. Let's look at how is Omlet different.
For example, the usage of
UserProfile and CompanyProfile components in the Profile are not detected by react-scanner. Instead, it reports the usage of a component called Component, which is the intermediary variable used for selecting the right profile component in this component.1
function Profile({ accountType }) {
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const components = {
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userProfile: UserProfile,
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companyProfile: CompanyProfile
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};
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const Component = components[accountType]
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return (
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<>
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...
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<Component>...</Component>
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</>
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);
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}
Dependency between
NamedComponentWrapped and ComponentUsingNamedWrappedComponent is missing in react-scanner results.export function ComponentUsingNamedWrappedComponent() {
return <NamedComponentWrapped/>;
}
export function NamedComponentWrapped() {
return <div></div>;
}
If you use use the below code as an example:
navigation.jsx
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import { Button, Input } from "./components";
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export function Footer() {
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return <div>
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<Button/>
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</div>;
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}
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export function Header() {
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return <div>
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<h1>Hello</h1>
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<Input/>
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</div>;
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}
react-scanner's usage detection result will be:
- Button in components/navigation.jsx
- Input in components/navigation.jsx
whereas Omlet will report the following:
- Footer uses Button
- Header uses Input
Instead, it detects names imported from modules. This causes duplicate components and incorrect usage numbers. For example if we use the below example…This results in 4 separate button components in react-scanner data since each of them has distinct import name and import path combinations:
- Button from components/Button
- Button from components/Button/Button
- SameButton from components/Button
- TheButton from components/Button
In react-scanners report, each combination has their separate usage counts where Omlet detects that they’re actually the same component and gives the total (correct) number of usages.
// file: components/Button/Button.jsx
export function Button() { .. }
// file: components/Button/index.jsx
import { Button } from "./Button";
export { Button };
export default Button;
// file app/pageA.jsx
import { Button } from "../components/Button";
// file app/pageB.jsx
import { Button } from "../components/Button/Button";
// file app/pageC.jsx
import SameButton from "../components/Button";
// file app/pageC.jsx
import TheButton from "../components/Button";
Aliased imports appear as separate components in react-scanner reports. Similar to the case mentioned under the Import resolution section, this causes fragmented usage counts and duplicate entries.
// file: frontend/src/layout/navigation/TopBar/SitePopover.tsx
import { ProfilePicture } from 'lib/lemon-ui/ProfilePicture'
// file: frontend/src/lib/lemon-ui/LemonTable/columnUtils.tsx
import { ProfilePicture } from '../ProfilePicture'
- HTML tags in JSX are not detected: Omlet doesn’t detect React element equivalent of HTML tags such as div, img, etc.
- Instance counts: Omlet doesn't count component instances. Instead, it reports unique parent components for each component. react-scanner reports each instance separately.
Last modified 1mo ago