[added] CustomPropTypes.singlePropFrom

Throw an error if multiple properties in the given list have a value

Author: aabenoja

src/utils/CustomPropTypes.js

@@ -22,7 +22,17 @@ let CustomPropTypes = {
    * @param componentName
    * @returns {Error|undefined}
    */
-  keyOf: createKeyOfChecker
+  keyOf: createKeyOfChecker,
+  /**
+   * Checks if only one of the listed properties is in use. An error is given
+   * if multiple have a value
+   *
+   * @param props
+   * @param propName
+   * @param componentName
+   * @returns {Error|undefined}
+   */
+  singlePropFrom: createSinglePropFromChecker
 };
 
 /**
@@ -80,4 +90,22 @@ function createKeyOfChecker(obj) {
   return createChainableTypeChecker(validate);
 }
 
+function createSinglePropFromChecker(arrOfProps) {
+  function validate(props, propName, componentName) {
+    const usedPropCount = arrOfProps
+      .map(listedProp => props[listedProp])
+      .reduce((acc, curr) => acc + (curr !== undefined ? 1 : 0), 0);
+
+    if (usedPropCount > 1) {
+      const [first, ...others] = arrOfProps;
+      const message = `${others.join(', ')} and ${first}`;
+      return new Error(
+        `Invalid prop '${propName}', only one of the following ` +
+        `may be provided: ${message}`
+      );
+    }
+  }
+  return validate;
+}
+
 export default CustomPropTypes;

test/CustomPropTypesSpec.js

@@ -47,4 +47,24 @@ describe('CustomPropTypes', function () {
       assert.isUndefined(validate('bar'));
     });
   });
+
+  describe('singlePropFrom', function () {
+    function validate(testProps) {
+      const propList = ['children', 'value'];
+
+      return CustomPropTypes.singlePropFrom(propList)(testProps, 'value', 'Component');
+    }
+
+    it('Should return undefined if only one listed prop in used', function () {
+      const testProps = {value: 5};
+
+      assert.isUndefined(validate(testProps));
+    });
+
+    it('Should return error if multiple of the listed properties have values', function () {
+      const testProps = {value: 5, children: 5};
+
+      validate(testProps).should.be.instanceOf(Error);
+    });
+  });
 });