add Input component

add Input component

src/utils/calcTextareaHeight.js

@@ -0,0 +1,108 @@
+// Thanks to
+// https://github.com/andreypopp/react-textarea-autosize/
+// https://github.com/ElemeFE/element/blob/master/packages/input/src/calcTextareaHeight.js
+
+let hiddenTextarea;
+
+const HIDDEN_STYLE = `
+    height:0 !important;
+    min-height:0 !important;
+    max-height:none !important;
+    visibility:hidden !important;
+    overflow:hidden !important;
+    position:absolute !important;
+    z-index:-1000 !important;
+    top:0 !important;
+    right:0 !important
+`;
+
+const 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) {
+    const style = window.getComputedStyle(node);
+
+    const boxSizing = style.getPropertyValue('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 contextStyle = CONTEXT_STYLE
+        .map(name => `${name}:${style.getPropertyValue(name)}`)
+        .join(';');
+
+    return {contextStyle, paddingSize, borderSize, boxSizing};
+}
+
+export default function calcTextareaHeight(targetNode, minRows = null, maxRows = null) {
+    if (!hiddenTextarea) {
+        hiddenTextarea = document.createElement('textarea');
+        document.body.appendChild(hiddenTextarea);
+    }
+
+    let {
+        paddingSize,
+        borderSize,
+        boxSizing,
+        contextStyle
+    } = calculateNodeStyling(targetNode);
+
+    hiddenTextarea.setAttribute('style', `${contextStyle};${HIDDEN_STYLE}`);
+    hiddenTextarea.value = targetNode.value || targetNode.placeholder || '';
+
+    let height = hiddenTextarea.scrollHeight;
+    let minHeight = -Infinity;
+    let maxHeight = Infinity;
+
+    if (boxSizing === 'border-box') {
+        height = height + borderSize;
+    } else if (boxSizing === 'content-box') {
+        height = height - paddingSize;
+    }
+
+    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: `${height}px`,
+        minHeight: `${minHeight}px`,
+        maxHeight: `${maxHeight}px`
+    };
+};