style: linter

README.md

@@ -1,12 +1,132 @@
 # Loan utils
 
 Project with different functions to calculate:
+
  -The minimun payment of a mortgage
+
+**Example parameters**:
+
+Loan = 150000.00
+
+Interest Rate: 7.5%, //format like 0.075
+
+Loan Length: 30 years, //format in months
+
+```
+import { getMonthlyPayment } from 'mortgate';
+
+const monthlyPayment = getMonthlyPayment(150e3, 7.5e-2, 30*12);
+```
 
  -The loan lenght of a mortgage
 
- -Calculate the new loan lenght adding an extra payment
+ **Example parameters**:
+
+Loan = 150000.00
+
+Interest Rate: 7.5%, //format like 0.075
+
+Mountly Payment: 2000.00
+
+```
+import { getLoanLength } from 'mortgate';
+
+const newLoanLenght = getLoanLength(150e3, 7.5e-2, 2000);
+```
 
  -The amortization table of the payoffs
+
+ **Example parameters**:
+
+Loan = 200000.00
+
+Interest Rate: 7.5% //format like 0.075
+
+Loan Length: 30 years //format in months
+
+Extra Payment = 1000
+
+Initial Date: number = Date.now() //format milliseconds
+
+Times Interest Compounds = 12 //default 12
+
+```
+import { getMortgagePayoff } from 'mortgate';
+
+const payoffData = getMortgagePayoff(2e5, 7.5e-2, 30 * 12, 1000);
+
+//payoffData
+{
+    mountlyPayment: 1398.429017105553,
+    extraPrincipal: 0,
+    interestRate: 0.075,
+    defaultTotalInterest: 303434.44615799905,
+    totalInterestWithSavings: 303434.4461580063,
+    loan: 200000,
+    defaultLoanLength: 360,
+    loanLength: 360,
+    startDate: 2020-09-28T08:44:15.873Z,
+    endDate: 2050-08-28T08:44:15.873Z,
+    defaultEndDate: 2050-08-28T08:44:15.873Z,
+    data: [{
+            date: 2050-09-28T08:44:15.873Z,
+            interest: 1250,
+            principal: 148.42901710555293,
+            principalExtra: 148.42901710555293,
+            balance: 199851.57098289445,
+          },
+          {
+            date: 2050-09-28T08:44:15.873Z,
+            interest: 1249.0723186430903,
+            principal: 149.35669846246265,
+            principalExtra: 149.35669846246265,
+            balance: 199702.214284432,
+          },
+          ...
+        ]
+    }
+
+```
 
  -Calculate simple interest and amortizing interest
+
+ **Total interest for a loan paying only the minimum monthly payment**
+ Use this function when you are going to calculate the lifetime interest using the minimun mountly payment.
+
+Loan = 200000.00
+
+Interest Rate: 7.5% //format like 0.075
+
+Loan Length: 30 years //format in months
+```
+import { getTotalInterest } from 'mortgate';
+
+
+const lifetimeInterest = getTotalInterest(2e5, 7.5e-2, 30 * 12);
+```
+
+ **Total interest for a loan paying a custom monthly payment**
+ Note: It could vary in a few decimal places far from the function getTotalInterest, by the method of recalculation of interest. 
+
+ **Example of variation**
+
+Using getTotalInterest: 303434.44615799905
+
+Using getTotalAmortizingInterest: 303434.4461580063
+
+Use getTotalAmortizingInterest if there is an Extra Payment Amount for the monthly payment
+
+Example
+
+Loan = 200000.00
+
+Interest Rate: 7.5% //format like 0.075
+
+Mountly Payment: 2000
+```
+import { getTotalAmortizingInterest } from 'mortgate';
+
+
+const lifetimeInterest = getTotalAmortizingInterest(2e5, 7.5e-2, 2000);
+```
+

src/index.ts

@@ -178,7 +178,7 @@ export const getLoanLength = (
  * @param {number} Interest rate annually
  * @param {number} Loan length express in months
  * @param {number} Extra payment add to the principal
- * @param {number} Date to start the payoff in miliseconds
+ * @param {number} Date to start the payoff in milliseconds
  * @param {number} Number of times interest compounds, default 12 (t)
  * @returns {object} Payoff Results
  */
@@ -196,9 +196,7 @@ export const getMortgagePayoff = (
   if (extraPrincipal < 0) throw new Error('Please provide a valid extra payment');
   if (timesInterestCompounds <= 0) throw new Error('Please provide a valid number of times interest compounds');
 
-  //Payoff results (Payments)
   const payoffGrid: any = [];
-
   let remainingLoan = loan;
   const defaultLoanLength = loanLength;
   const defaultInitialDate = initialDate;
@@ -215,7 +213,7 @@ export const getMortgagePayoff = (
     interestRate,
     defaultTotalInterest,
     totalInterestWithSavings: getTotalAmortizingInterest(loan, interestRate, mountlyPayment, timesInterestCompounds),
-    loan: loan,
+    loan,
     defaultLoanLength: loanLength,
     loanLength: newLoanLength,
     startDate: new Date(initialDate),
@@ -231,38 +229,34 @@ export const getMortgagePayoff = (
     const dateRow = date;
     const interestRow = getSimpleInterest(remainingLoan, interestRate);
     const principal = mountlyPayment - interestRow;
-    let principalExtra = principal + extraPrincipal;
+    const principalExtra = principal + extraPrincipal;
     let balance = remainingLoan - principalExtra;
 
     /*
      * Stop Condition
      */
     if (remainingLoan + interestRow < mountlyPayment + extraPrincipal) {
-      const row = {
+      payoffGrid.push({
         date: dateRow,
         interest: interestRow,
         principal,
         principalExtra: principalExtra + balance,
         balance: 0,
-        type: 'row',
-      };
-      payoffGrid.push(row);
-      remainingLoan = balance = 0; //remaining loan
+      });
+      remainingLoan = balance = 0;
       break;
     }
 
     /*
      * Add row to the payoff Grid
      */
-    const row = {
+    payoffGrid.push({
       date: dateRow,
       interest: interestRow,
       principal,
       principalExtra,
       balance,
-      type: 'row',
-    };
-    payoffGrid.push(row);
+    });
 
     /*
      * Update conditions for next iteration
@@ -272,13 +266,14 @@ export const getMortgagePayoff = (
   }
 
   results.data = payoffGrid;
+  console.log(results);
   return results;
 };
 
 /*
  * Calculate end date of the loan
  *
- * @param {number} date in miliseconds
+ * @param {number} date in milliseconds
  * @param {number} loan Length
  * @returns {string} end date of the loan
  */