Parameter: paramValues: Setter Refactor

This commit refactors the paramValues setter to use Array.every and
avoid the performance hit from using forEach.

This commit also adds the isParamValue static validator to the Parameter
class. This is used by the Array.every call, and should probably be
moved eventually to a validator class that should also be built.
Signed-off-by: Mark Stenglein <mark@stengle.in>

src/Parameter.ts

@@ -132,19 +132,16 @@ export default class Parameter implements ICalElement {
      * @throws TypeError if any of the input values are not valid param-value's
      */
     set paramValues(newValues: string[]) {
-        newValues.forEach(newValue => {
-            if (
-                !((Parameter.isParamText(newValue)) ||
-                (Parameter.isQuotedString(newValue)))
-            ) {
-                throw new TypeError(
-                    "param-value must either be valid paramtext or" +
-                        " quoted-string"
-                );
-            }
-        });
-
-        this._paramValues = newValues;
+        // Ensure each paramValue is valid ParamText or QuotedString
+        if (!(newValues.every(Parameter.isParamValue))) {
+            throw new TypeError(
+                "param-value must either be valid paramtext or quoted-string"
+            );
+        }
+        // Write paramValues
+        else {
+            this._paramValues = newValues;
+        }
     }
 
 
@@ -174,21 +171,21 @@ export default class Parameter implements ICalElement {
      * @returns string Representation of the Parameter as defined in RFC 5545
      */
     public generate(): string {
-        let outputString = this.paramName + "=";
-        /**
-         * Goes through each parameter value and adds it, being sure to place
-         * the comma for the 2nd parameter onwards.
-         */
-        for (let i = 0; i < this.paramValues.length; i++) {
-            if (i !== 0) {
-                outputString += ",";
-            }
-            outputString += this.paramValues[i];
-        }
-
-        return outputString;
+        return `${this.paramName}=${this.paramValues.join(",")}`;
     }
 
+    /**
+     * Checks to see if the input string is proper paramValue
+     *
+     * @author Mark Stenglein <mark@stengle.in>
+     * @since 0.1.0
+     * @param input Input string to be tested
+     * @returns boolean result
+     */
+    public static isParamValue(input: string): boolean {
+        return Parameter.isParamText(input) ||
+            Parameter.isQuotedString(input);
+    }
 
     /**
      * Checks to see if the input string is a compliant iama-token