Force resize calcs based on new optional width prop

src/Truncate.js

@@ -10,14 +10,16 @@ export default class Truncate extends Component {
             PropTypes.number
         ]),
         trimWhitespace: PropTypes.bool,
+        width: PropTypes.number,
         onTruncate: PropTypes.func
     };
 
     static defaultProps = {
         children: '',
         ellipsis: '…',
         lines: 1,
-        trimWhitespace: false
+        trimWhitespace: false,
+        width: 0
     };
 
     state = {};
@@ -62,6 +64,11 @@ export default class Truncate extends Component {
         if (this.props.children !== prevProps.children) {
             this.forceUpdate();
         }
+
+        // If the width prop has changed, recalculate size of contents
+        if (this.props.width !== prevProps.width) {
+            this.calcTargetWidth();
+        }
     }
 
     componentWillUnmount() {

test/Truncate.js

@@ -447,6 +447,24 @@ describe('<Truncate />', () => {
             }
         });
 
+        it('should recalculate when the width property changes', () => {
+            const calcTargetWidth = sinon.spy(Truncate.prototype, 'calcTargetWidth');
+
+            try {
+                const container = document.createElement('div');
+
+                render(<Truncate width={100} />, container);
+
+                const numCalled = calcTargetWidth.callCount;
+
+                render(<Truncate width={200} />, container);
+
+                expect(calcTargetWidth, 'was called times', numCalled + 1);
+            } finally {
+                Truncate.prototype.calcTargetWidth.restore();
+            }
+        });
+
         it('should clean up all event listeners on window when unmounting', () => {
             const events = new Set();