using closures to give the effect of private class fields

scripts/classes/data-saver.js

@@ -1,121 +1,122 @@
-let fepperUiInst;
+// TODO: Replace closure with private class field when there is greater browser support.
+export default function (cookieName, fepperUiInst) {
+  class DataSaver {
+
+    /**
+     * Data Saver. Namespaced cookie-handling methods.
+     *
+     * @param {string} cookieName - The name of the cookie to store the data in.
+     * @param {object} fepperUi - The Fepper UI instance.
+     */
+    constructor(cookieName, fepperUi) { // eslint-disable-line no-unused-vars
+      this.cookieName = cookieName;
+    }
 
-export default class {
+    // In case fepperUi.cookies is undefined at instantiation.
+    get cookies() {
+      return fepperUiInst.cookies;
+    }
 
-  /**
-   * Data Saver. Namespaced cookie-handling methods.
-   *
-   * @param {string} cookieName - The name of the cookie to store the data in.
-   * @param {object} fepperUi - The Fepper UI instance.
-   */
-  constructor(cookieName, fepperUi) {
-    fepperUiInst = fepperUi;
+    // Methods.
 
-    this.cookieName = cookieName;
-  }
+    /**
+     * Add a given value to the cookie. Do not update if it already exists.
+     *
+     * @param {string} name - The name of the key.
+     * @param {string} val - The value.
+     */
+    addValue(name, val) {
+      const cookieValOrig = this.cookies.get(this.cookieName);
+      let cookieValNew = name + '~' + val;
 
-  // In case fepperUi.cookies is undefined at instantiation.
-  get cookies() {
-    return fepperUiInst.cookies;
-  }
+      if (cookieValOrig) {
+        cookieValNew = cookieValOrig + '|' + cookieValNew;
+      }
 
-  // Methods.
+      this.cookies.set(this.cookieName, cookieValNew);
+    }
 
-  /**
-   * Add a given value to the cookie. Do not update if it already exists.
-   *
-   * @param {string} name - The name of the key.
-   * @param {string} val - The value.
-   */
-  addValue(name, val) {
-    const cookieValOrig = this.cookies.get(this.cookieName);
-    let cookieValNew = name + '~' + val;
+    /**
+     * Update a value found in the cookie. If the key doesn't exist, add the value.
+     *
+     * @param {string} name - The name of the key.
+     * @param {string} val - The value.
+     */
+    updateValue(name, val) {
+      if (this.findValue(name)) {
+        const cookieVal = this.cookies.get(this.cookieName) || '';
+        const cookieVals = cookieVal.split('|');
+        let cookieValNew = '';
+
+        for (let i = 0; i < cookieVals.length; i++) {
+          const fieldVals = cookieVals[i].split('~');
+
+          if (fieldVals[0] === name) {
+            fieldVals[1] = val;
+          }
+
+          if (i) {
+            cookieValNew += '|';
+          }
+
+          cookieValNew += fieldVals[0] + '~' + fieldVals[1];
+        }
 
-    if (cookieValOrig) {
-      cookieValNew = cookieValOrig + '|' + cookieValNew;
+        this.cookies.set(this.cookieName, cookieValNew);
+      }
+      else {
+        this.addValue(name, val);
+      }
     }
 
-    this.cookies.set(this.cookieName, cookieValNew);
-  }
-
-  /**
-   * Update a value found in the cookie. If the key doesn't exist, add the value.
-   *
-   * @param {string} name - The name of the key.
-   * @param {string} val - The value.
-   */
-  updateValue(name, val) {
-    if (this.findValue(name)) {
+    /**
+     * Remove the given key.
+     *
+     * @param {string} name - The name of the key.
+     */
+    removeValue(name) {
       const cookieVal = this.cookies.get(this.cookieName) || '';
       const cookieVals = cookieVal.split('|');
+      let k = 0;
       let cookieValNew = '';
 
       for (let i = 0; i < cookieVals.length; i++) {
         const fieldVals = cookieVals[i].split('~');
 
-        if (fieldVals[0] === name) {
-          fieldVals[1] = val;
-        }
+        if (fieldVals[0] !== name) {
+          if (k) {
+            cookieValNew += '|';
+          }
 
-        if (i) {
-          cookieValNew += '|';
+          cookieValNew += fieldVals[0] + '~' + fieldVals[1];
+          k++;
         }
-
-        cookieValNew += fieldVals[0] + '~' + fieldVals[1];
       }
 
       this.cookies.set(this.cookieName, cookieValNew);
     }
-    else {
-      this.addValue(name, val);
-    }
-  }
-
-  /**
-   * Remove the given key.
-   *
-   * @param {string} name - The name of the key.
-   */
-  removeValue(name) {
-    const cookieVal = this.cookies.get(this.cookieName) || '';
-    const cookieVals = cookieVal.split('|');
-    let k = 0;
-    let cookieValNew = '';
-
-    for (let i = 0; i < cookieVals.length; i++) {
-      const fieldVals = cookieVals[i].split('~');
-
-      if (fieldVals[0] !== name) {
-        if (k) {
-          cookieValNew += '|';
-        }
 
-        cookieValNew += fieldVals[0] + '~' + fieldVals[1];
-        k++;
-      }
-    }
+    /**
+     * Find the value using the given key.
+     *
+     * @param {string} name - The name of the key.
+     * @returns {string} The value of the key or empty string if the value isn't found.
+     */
+    findValue(name) {
+      const cookieVal = this.cookies.get(this.cookieName) || '';
+      const cookieVals = cookieVal.split('|');
 
-    this.cookies.set(this.cookieName, cookieValNew);
-  }
+      for (let i = 0; i < cookieVals.length; i++) {
+        const fieldVals = cookieVals[i].split('~');
 
-  /**
-   * Find the value using the given key.
-   *
-   * @param {string} name - The name of the key.
-   * @returns {string} The value of the key or empty string if the value isn't found.
-   */
-  findValue(name) {
-    const cookieVal = this.cookies.get(this.cookieName) || '';
-    const cookieVals = cookieVal.split('|');
-
-    for (let i = 0; i < cookieVals.length; i++) {
-      const fieldVals = cookieVals[i].split('~');
-
-      if (fieldVals[0] === name) {
-        return fieldVals[1];
+        if (fieldVals[0] === name) {
+          return fieldVals[1];
+        }
       }
-    }
 
-    return '';
+      return '';
+    }
   }
+
+  return new DataSaver(cookieName, fepperUiInst);
 }