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trikitrok/QuarterlyReportGenerator.ts

Created March 22, 2025 11:50
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Sprout Class example
Raw
QuarterlyReportGenerator.ts
//////////////////////////////////////////////////
// Step 1: Identify the change point and determine the sprouted class interface
export class QuarterlyReportGenerator {
public readonly beginDate: Date;
public readonly endDate: Date;
public readonly database: Database;
constructor() {
// constructor with multiple side effects
}
public generate(): string {
const results = this.database.queryResults(this.beginDate, this.endDate);
let pageText = "<html><head><title>" +
"Quarterly Report" +
"</title></head><body><table>";
// <-- this is the change point
if (results.length !== 0) {
for (const result of results) {
pageText += "<tr>";
pageText += `<td>${result.department}</td>`;
pageText += `<td>${result.manager}</td>`;
pageText += `<td>${result.netProfit}</td>`;
pageText += `<td>${result.operatingExpense}</td>`;
pageText += "</tr>";
}
} else {
pageText += "No results for this period";
}
pageText += "</table>";
pageText += "</body>";
pageText += "</html>";
return pageText;
}
}
//////////////////////////////////////////////////
// Step 2: Develop the sprouted class with tests
export class QuarterlyReportTableHeaderProducer {
public makeHeader(): string {
return "<tr><td>Department</td><td>Manager</td>" +
"<tr><td>Profit</td><td>Expenses</td>";
}
}
////////////////////////////////////////////////////
// Step 3: Instance the sprout class and call its method from the source method
export class QuarterlyReportGenerator {
// rest of the code omitted for the sake of brevity...
public generate(): string {
const results = this.database.queryResults(this.beginDate, this.endDate);
let pageText = "<html><head><title>" +
"Quarterly Report" +
"</title></head><body><table>";
const producer = new QuarterlyReportTableHeaderProducer(); // <-- call to the sprouted class
pageText += producer.makeHeader();
if (results.length !== 0) {
for (const result of results) {
pageText += "<tr>";
pageText += `<td>${result.department}</td>`;
pageText += `<td>${result.manager}</td>`;
pageText += `<td>${result.netProfit}</td>`;
pageText += `<td>${result.operatingExpense}</td>`;
pageText += "</tr>";
}
} else {
pageText += "No results for this period";
}
pageText += "</table>";
pageText += "</body>";
pageText += "</html>";
return pageText;
}
}
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