textarea

2023年07月18日

柏拉文

越努力，越幸运

一、认识

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二、语法

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2.1 受控

2.2 非受控

三、属性

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四、事件

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五、实践

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5.1 高度自适应

import { useState } from 'react';

function App() {
  const [value, setValue] = useState<string>('');

  const handleTextareaChange = (e: any) => {
    const style = getComputedStyle(e.target);
    const lineHeight = parseInt(style.lineHeight.slice(0, -2), 10);
    let height = parseInt(style.height.slice(0, -2), 10);

    if (e.target.scrollHeight > height) {
      e.target.style.height = `${e.target.scrollHeight + 2}px`;
    } else {
      while (height >= e.target.scrollHeight) {
        e.target.style.height = `${height - lineHeight}px`;
        height -= lineHeight;
      }
      e.target.style.height = `${height + lineHeight}px`;
    }

    setValue(e.target.value);
  };

  return (
    <div>
      <textarea
        value={value}
        onChange={handleTextareaChange}
        style={{
          resize: 'none',
          height: '36px',
          lineHeight: '20px',
          boxSizing: 'border-box'
        }}
      ></textarea>
    </div>
  );
}

export default App;

六、故障

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