@yncoder/element-react/dist/npm/es6/src/input/calcTextareaHeight.js

Element UI for React

var hiddenTextarea = void 0;

var HIDDEN_STYLE = '\n  height:0 !important;\n  visibility:hidden !important;\n  overflow:hidden !important;\n  position:absolute !important;\n  z-index:-1000 !important;\n  top:0 !important;\n  right:0 !important\n';

var CONTEXT_STYLE = ['letter-spacing', 'line-height', 'padding-top', 'padding-bottom', 'font-family', 'font-weight', 'font-size', 'text-rendering', 'text-transform', 'width', 'text-indent', 'padding-left', 'padding-right', 'border-width', 'box-sizing'];

function calculateNodeStyling(node) {
  var style = window.getComputedStyle(node);

  var boxSizing = style.getPropertyValue('box-sizing');

  var paddingSize = parseFloat(style.getPropertyValue('padding-bottom')) + parseFloat(style.getPropertyValue('padding-top'));

  var borderSize = parseFloat(style.getPropertyValue('border-bottom-width')) + parseFloat(style.getPropertyValue('border-top-width'));

  var contextStyle = CONTEXT_STYLE.map(function (name) {
    return name + ':' + style.getPropertyValue(name);
  }).join(';');

  return { contextStyle: contextStyle, paddingSize: paddingSize, borderSize: borderSize, boxSizing: boxSizing };
}

export default function calcTextareaHeight(targetNode) {
  var minRows = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : null;
  var maxRows = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : null;

  if (!hiddenTextarea) {
    hiddenTextarea = document.createElement('textarea');
    document.body && document.body.appendChild(hiddenTextarea);
  }

  var _calculateNodeStyling = calculateNodeStyling(targetNode),
      paddingSize = _calculateNodeStyling.paddingSize,
      borderSize = _calculateNodeStyling.borderSize,
      boxSizing = _calculateNodeStyling.boxSizing,
      contextStyle = _calculateNodeStyling.contextStyle;

  hiddenTextarea.setAttribute('style', contextStyle + ';' + HIDDEN_STYLE);
  hiddenTextarea.value = targetNode.value || targetNode.placeholder || '';

  var height = hiddenTextarea.scrollHeight;

  if (boxSizing === 'border-box') {
    height = height + borderSize;
  } else if (boxSizing === 'content-box') {
    height = height - paddingSize;
  }

  hiddenTextarea.value = '';
  var singleRowHeight = hiddenTextarea.scrollHeight - paddingSize;

  if (minRows !== null) {
    var minHeight = singleRowHeight * minRows;
    if (boxSizing === 'border-box') {
      minHeight = minHeight + paddingSize + borderSize;
    }
    height = Math.max(minHeight, height);
  }
  if (maxRows !== null) {
    var maxHeight = singleRowHeight * maxRows;
    if (boxSizing === 'border-box') {
      maxHeight = maxHeight + paddingSize + borderSize;
    }
    height = Math.min(maxHeight, height);
  }

  return { height: height + 'px' };
}