diff --git a/rainbowjyp/chp6/CombineFunctionIntoClass.js b/rainbowjyp/chp6/CombineFunctionIntoClass.js
new file mode 100644
index 0000000..289ce25
--- /dev/null
+++ b/rainbowjyp/chp6/CombineFunctionIntoClass.js
@@ -0,0 +1,37 @@
+class Reading {
+    constructor(data) {
+        this._customer = data.customer;
+        this._quantity = data.quantity;
+        this._month = data.month;
+        this._year = data.year;
+    }
+
+    get customer() {
+        return this._customer;
+    }
+    get quantity() {
+        return this._quantity;
+    }
+    get month() {
+        return this._month;
+    }
+    get year() {
+        return this._year;
+    }
+
+    get baseCharge() {
+        return baseRate(this.month, this.year) * this.quantity;
+    }
+
+    get taxableCharge() {
+        return Math.max(0, this.baseCharge - taxThreshold(this.year));
+    }
+}
+
+const rawReading = acquireReading();
+const aReading = new Reading(rawReading);
+const taxableCharge = aReading.taxableCharge;
+
+function acquireReading() {
+    return { customer: 'ivan', quantity: 10, month: 5, year: 2017 };
+}
diff --git a/rainbowjyp/chp6/extractFunction.js b/rainbowjyp/chp6/extractFunction.js
new file mode 100644
index 0000000..c7d3559
--- /dev/null
+++ b/rainbowjyp/chp6/extractFunction.js
@@ -0,0 +1,33 @@
+function printOwing(invoice) {
+    printBanner();
+    const outstanding = calculateOutstanding(invoice);
+
+    recordDueDate(invoice);
+
+    printDetails(invoice, outstanding);
+}
+
+function calculateOutstanding(invoice) {
+    let result = 0;
+    for (const o of invoice.orders) {
+        result += o.amount;
+    }
+    return result;
+}
+
+function recordDueDate(invoice) {
+    const today = Clock.today;
+    invoice.dueDate = new Date(today.getFullYear(), today.getMonth(), today.getDate() + 30);
+}
+
+function printBanner() {
+    console.log('***********************');
+    console.log('*** Customer Owes ***');
+    console.log('***********************');
+}
+
+function printDetails(invoice, outstanding) {
+    console.log(`name: ${invoice.customer}`);
+    console.log(`amount: ${outstanding}`);
+    console.log(`due: ${invoice.dueDate.toLocaleDateString()}`);
+}
diff --git a/rainbowjyp/chp6/splitPhase.js b/rainbowjyp/chp6/splitPhase.js
new file mode 100644
index 0000000..6ce9916
--- /dev/null
+++ b/rainbowjyp/chp6/splitPhase.js
@@ -0,0 +1,20 @@
+function priceOrder(product, quantity, shippingMethod) {
+    const priceData = calculatePricingData(product, quantity);
+    return applyShipping(priceData, shippingMethod);
+}
+
+const calculatePricingData = (product, quantity) => {
+    const basePrice = product.basePrice * quantity;
+    const discount = Math.max(quantity - product.discountThreshold, 0) * product.basePrice * product.discountRate;
+    return { basePrice: basePrice, quantity: quantity, discount: discount };
+};
+
+function applyShipping(priceData, shippingMethod) {
+    const shippingPerCase =
+        priceData.basePrice > shippingMethod.discountThreshold
+            ? shippingMethod.discountedFee
+            : shippingMethod.feePerCase;
+    const shippingCost = priceData.quantity * shippingPerCase;
+    const price = priceData.basePrice - priceData.discount + shippingCost;
+    return price;
+}