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Stefan Judis
Stefan Judis

Posted on • Originally published at stefanjudis.com

A React "if component"

#javascript #react

After using Vue and Angular.js (I used the first version of Angular when it came out) for many years, I have to say that I always enjoyed the simplicity of using v-if and ng-if to render child components conditionally.

Now I'm writing React primarily and honestly I'm bothered by the constant use of ternary operators when dealing with conditionally rendered components.

function SomeComponent({condition}) {
  return <div>
    { condition ? <span>Yes it is true!</span> : null }
  </div>
}
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It's not a big deal, and there are many different ways to render boolean-dependent components, but I find myself writing code such as the above repeatedly.

Today I read 7 Ways of Achieving Conditional Rendering in React, and it included a handy snippet that I'll adopt from now on.

A conditional if component

I can't say that I didn't consider abstracting the ternary operators away, but somehow I never took it into practice. Fernando Doglio's article now moved me over the line to adopt a nicer pattern. Say hi to the functional if component.

function IF({children, condition}) {
  if (condition) {
    // render children if the condition is truthy
    return children;
  }

  return null;
}

/**
 * Use the component as follows:
 *
 * <IF condition={condition}>
 *   <Greeter username={user.name} />
 * </IF>
 */
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It's seven lines of code and this tiny component can be brought into any React project as handy utility. Much better! Thank you Fernando!

Top comments (6)

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stereoplegic profile image
Mike Bybee • • Edited

I personally think ternaries are fine, but expanding on your solution:

By adding a third else = null prop (and return else instead of return null), you can default to null while allowing for an actual value on the other side of the ternary e.g.

function IF({children, condition, else = null}) {
  if (condition) {
    // render children if the condition is truthy
    return children;
  }

  return else;
}

/**
 * Use the component as follows:
 *
 * <IF condition={condition}>
 *   <Greeter username={user.name} />
 * </IF>
 *
 * With 'else' prop, equivalent to
 * {condition ? <Greeter  username={user.name} /> : <LoginButton />}
 *
 * const renderElse = () => <LoginButton />
 * <IF condition={condition} else={renderElse}>
 *   <Greeter username={user.name} />
 * </IF>
 *
 *
 */
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You could even take it further with another prop, an array of objects in the shape of {extraCondition, extraReturn}, for else if scenarios (that's going to take too much typing to give an example of the additional logic on my phone, but I hope you get the gist).

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shadowtime2000 profile image
shadowtime2000 •

May also be pretty nice to use React.memo on it, just for performance.

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shadowtime2000 profile image
shadowtime2000 • 
import { memo } from "react";

function If({ children, condition }) {
    return condition ? children : null;
}

export default memo(If, (props, oldProps) => props.condition === oldProps.condition);
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koire profile image
Koire •

This is a really good expression of it.
I've been trying to do something very similar since we have something like

<Title> {newAccount ? "newtitle": "oldtitle"}</Title>
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but we have a few ways for newAccount to be true
something like

<IF condition={isNewAccount}> This is a new account</IF>
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is a start

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josdejong profile image
Jos de Jong • • Edited

I do like this solution. We've used this in the past but reverted this again soon: it led to performance issues.

Unlike the ternary operator a ? b : c or &&, this <IF>...</IF> component will always create and render its inner contents (children), and in case the condition is false, the rendered children is only ignored by <IF> in the end. That can be very expensive.

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griffadev profile image
George Griffiths •

This feels like going back around to html templating languages like handlebars or nunjucks or ejs and I don't hate that

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