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// Thanks to https://github.com/andreypopp/react-textarea-autosize/
/**
* calculateNodeHeight(uiTextNode, useCache = false)
*/
const HIDDEN_TEXTAREA_STYLE = `
min-height:0 !important;
max-height:none !important;
height:0 !important;
visibility:hidden !important;
overflow:hidden !important;
position:absolute !important;
z-index:-1000 !important;
top:0 !important;
right:0 !important
`;
const SIZING_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',
];
let computedStyleCache = {};
let hiddenTextarea;
function calculateNodeStyling(node, useCache = false) {
const nodeRef = (
node.getAttribute('id') ||
node.getAttribute('data-reactid') ||
node.getAttribute('name')
);
if (useCache && computedStyleCache[nodeRef]) {
return computedStyleCache[nodeRef];
}
const style = window.getComputedStyle(node);
const boxSizing = (
style.getPropertyValue('box-sizing') ||
style.getPropertyValue('-moz-box-sizing') ||
style.getPropertyValue('-webkit-box-sizing')
);
const paddingSize = (
parseFloat(style.getPropertyValue('padding-bottom')) +
parseFloat(style.getPropertyValue('padding-top'))
);
const borderSize = (
parseFloat(style.getPropertyValue('border-bottom-width')) +
parseFloat(style.getPropertyValue('border-top-width'))
);
const sizingStyle = SIZING_STYLE
.map(name => `${name}:${style.getPropertyValue(name)}`)
.join(';');
const nodeInfo = {
sizingStyle,
paddingSize,
borderSize,
boxSizing,
};
if (useCache && nodeRef) {
computedStyleCache[nodeRef] = nodeInfo;
}
return nodeInfo;
}
export default function calculateNodeHeight(
uiTextNode,
useCache = false,
minRows: number | null = null,
maxRows: number | null = null
) {
if (!hiddenTextarea) {
hiddenTextarea = document.createElement('textarea');
document.body.appendChild(hiddenTextarea);
}
// Copy all CSS properties that have an impact on the height of the content in
// the textbox
let {
paddingSize, borderSize,
boxSizing, sizingStyle,
} = calculateNodeStyling(uiTextNode, useCache);
// Need to have the overflow attribute to hide the scrollbar otherwise
// text-lines will not calculated properly as the shadow will technically be
// narrower for content
hiddenTextarea.setAttribute('style', `${sizingStyle};${HIDDEN_TEXTAREA_STYLE}`);
hiddenTextarea.value = uiTextNode.value || uiTextNode.placeholder || '';
let minHeight = -Infinity;
let maxHeight = Infinity;
let height = hiddenTextarea.scrollHeight;
if (boxSizing === 'border-box') {
// border-box: add border, since height = content + padding + border
height = height + borderSize;
} else if (boxSizing === 'content-box') {
// remove padding, since height = content
height = height - paddingSize;
}
if (minRows !== null || maxRows !== null) {
// measure height of a textarea with a single row
hiddenTextarea.value = '';
let singleRowHeight = hiddenTextarea.scrollHeight - paddingSize;
if (minRows !== null) {
minHeight = singleRowHeight * minRows;
if (boxSizing === 'border-box') {
minHeight = minHeight + paddingSize + borderSize;
}
height = Math.max(minHeight, height);
}
if (maxRows !== null) {
maxHeight = singleRowHeight * maxRows;
if (boxSizing === 'border-box') {
maxHeight = maxHeight + paddingSize + borderSize;
}
height = Math.min(maxHeight, height);
}
}
return { height, minHeight, maxHeight };
}