Renders a tooltip component.

  • Use the React.useState() hook to create the show variable and initialize it to false.
  • Return a <div> element that contains the <div> that will be the tooltip and the children passed to the component.
  • Handle the onMouseEnter and onMouseLeave methods, by altering the value of the show variable.

继续阅读 30秒学会 React 片段 – Tooltip

A hook that handles the event of clicking outside of the wrapped component.

  • Create a custom hook that takes a ref and a callback to handle the click event.
  • Use the React.useEffect() hook to append and clean up the click event.
  • Use the React.useRef() hook to create a ref for your click component and pass it to the useClickOutside hook.

继续阅读 30秒学会 React 片段 – useClickOutside

Renders an <input> element that uses a callback function to pass its value to the parent component.

  • Use object destructuring to set defaults for certain attributes of the <input> element.
  • Render an <input> element with the appropriate attributes and use the callback function in the onChange event to pass the value of the input to the parent.

继续阅读 30秒学会 React 片段 – UncontrolledInput

A hook that implements fetch in a declarative manner.

  • Create a custom hook that takes a url and options.
  • Use the React.useState() hook to initialize the response and error state variables.
  • Use the React.useEffect() hook to anychronously call fetch() and update the state varaibles accordingly.
  • Return an object containting the response and error state variables.

继续阅读 30秒学会 React 片段 – useFetch

Renders a textarea component with a character limit.

  • Use the React.useState() hook to create the content state variable and set its value to value.
    Create a method setFormattedContent, which trims the content of the input if it’s longer than limit.
  • Use the React.useEffect() hook to call the setFormattedContent method on the value of the content state variable.
  • Use a<div> to wrap both the<textarea> and the <p> element that displays the character count and bind the onChange event of the <textarea> to call setFormattedContent with the value of event.target.value.

继续阅读 30秒学会 React 片段 – LimitedTextarea

Renders a toggle component.

  • Use the React.useState() to initialize the isToggleOn state variable to false.
  • Use an object, style, to hold the styles for individual components and their states.
  • Return a <button> that alters the component’s isToggledOn when its onClick event is fired and determine the appearance of the content based on isToggleOn, applying the appropriate CSS rules from the style object.

继续阅读 30秒学会 React 片段 – Toggle

Renders a <select> element that uses a callback function to pass its value to the parent component.

  • Use object destructuring to set defaults for certain attributes of the <select> element.
  • Render a <select> element with the appropriate attributes and use the callback function in the onChange event to pass the value of the textarea to the parent.
  • Use destructuring on the values array to pass an array of value and text elements and the selected attribute to define the initial value of the <select> element.

继续阅读 30秒学会 React 片段 – Select

Renders an <input> element with internal state, that uses a callback function to pass its value to the parent component.

  • Use object destructuring to set defaults for certain attributes of the <input> element.
  • Use the React.setState() hook to create the value state variable and give it a value of equal to the defaultValue prop.
  • Use the React.useEffect() hook with a second parameter set to the value state variable to call the callback function every time value is updated.
  • Render an <input> element with the appropriate attributes and use the the onChange event to upda the value state variable.

继续阅读 30秒学会 React 片段 – ControlledInput

Renders a string as plaintext, with URLs converted to appropriate <a> elements.

  • Use String.prototype.split() and String.prototype.match() with a regular expression to find URLs in a string.
  • Return a <React.Fragment> with matched URLs rendered as <a> elements, dealing with missing protocol prefixes if necessary, and the rest of the string rendered as plaintext.

继续阅读 30秒学会 React 片段 – AutoLink

A hook that implements setTimeout in a declarative manner.

  • Create a custom hook that takes a callback and a delay.
  • Use the React.useRef() hook to create a ref for the callback function.
  • Use the React.useEffect() hook to remember the latest callback.
  • Use the React.useEffect() hook to set up the timeout and clean up.

继续阅读 30秒学会 React 片段 – useTimeout