Warning: Received `false` for a non-boolean attribute. How do I pass a boolean for a custom boolean attribute?

Try this instead:

comingsoon={value ? 1 : 0}

As of 5.1 you can now use transient props ($) which prevents the props being passed to the DOM element.

const Comp = styled.div`
  color: ${props =>
    props.$draggable || 'black'};
`;

render(
  <Comp $draggable="red" draggable="true">
    Drag me!
  </Comp>
);

You have to add $ prefix to attribute:

$comingsoon={value}

Styled Components had added transient props in 5.1 version: https://styled-components.com/docs/api#transient-props

In my case, it was because I was accidentally passing {...@props} down into a div.

Usually passing attribute={false} is fine, but not to native elements.

Similar to Frank Lins answer above but I had to use undefined instead of 0 to get rid of the warning:

comingsoon={value ? 1 : undefined}

Just make it a number instead, this is the workaround from https://github.com/styled-components/styled-components/issues/1198:

This error with styled-components appears to be due to styled() attempting to apply a boolean to an element in the DOM, but DOM elements only accept strings as attributes.

This is well documented in the styled-components repository here: https://github.com/styled-components/styled-components/issues/1198

There are two solutions:

1. Lift the styled component w/ the passed attribute up, so that the attribute is not applied to the element directly. Or,

2. Filter the passed attribute out of the props when calling styled components.

Both of these options are demonstrated in the code below.

CodeSandbox: https://codesandbox.io/s/cool-thunder-9w132?file=/src/App.tsx

import React, { useState } from "react";
import styled from 'styled-components';

// demonstration of two different solutions for solving the styled-components error:
// `Warning: Received `false` for a non-boolean attribute`
// Solution 1: Lift the attribute up into a wrapper.
// Solution 2: Filter-out the `toggle` attribute passed to styled-component.

interface BtnProps {
  toggle: boolean;
}

const Container = styled.div`
  width: 100%;
  height: 500px;
  display: flex;
  flex-direction: row;
  justify-content: space-around;
  align-items: center;
`;

const StyledBtnOne = styled.div<BtnProps>`
  & button {
    background-color: ${({toggle}) => toggle ? ' #2ecc71' : '' };
  };
`;

const StyledBtnTwo = styled(({primary, ...props}) =>
  <button {...(({toggle, ...propz}) => propz)(props)} />)<BtnProps>`
  background-color: ${({toggle}) => toggle ? ' #3498db' : '' };
`;

const App = () => {

  const [ btnOne, setBtnOne ] = useState(false);

  const [ btnTwo, setBtnTwo ] = useState(false);

  const triggerOne = () => setBtnOne(!btnOne);

  const triggerTwo = () => setBtnTwo(!btnTwo);

  return (
    <Container>
      <StyledBtnOne toggle={btnOne}>
        <button 
          onClick={triggerOne}>
            Solution 1
        </button>
      </StyledBtnOne>

      <StyledBtnTwo 
        toggle={btnTwo}
        onClick={triggerTwo}>
        Solution 2
      </StyledBtnTwo>
    </Container>
  );

}

export default App;

Solved this by enclosing with brackets {} the boolean variable I was passing through props.

const childrenWithProps = React.Children.map(props.children, child => {
  return React.cloneElement(child, { showcard: { showCard } }
)});

This warning can be caused also if the property of styled component has the name existing in HTML. For example I had such issue when named property wrap. After renaming warning disappeared.