react/docs/tips/06-style-props-value-px.md

id	title	layout	permalink	prev	next
style-props-value-px	Shorthand for Specifying Pixel Values in style props	tips	style-props-value-px.html	maximum-number-of-jsx-root-nodes.html	children-props-type.html

When specifying a pixel value for your inline style prop, React automatically appends the string "px" for you after your number value, so this works:

var divStyle = {height: 10}; // rendered as "height:10px"
ReactDOM.render(<div style={divStyle}>Hello World!</div>, mountNode);

See Inline Styles for more info.

Sometimes you do want to keep the CSS properties unitless. Here's a list of properties that won't get the automatic "px" suffix:

• animationIterationCount
• boxFlex
• boxFlexGroup
• boxOrdinalGroup
• columnCount
• fillOpacity
• flex
• flexGrow
• flexPositive
• flexShrink
• flexNegative
• flexOrder
• fontWeight
• lineClamp
• lineHeight
• opacity
• order
• orphans
• stopOpacity
• strokeDashoffset
• strokeOpacity
• strokeWidth
• tabSize
• widows
• zIndex
• zoom