12-insertmethod-one.diff

class Histogram {
	filename: string
	index: number
	rows: string[][] = []
	members: number[] = []
	histogram: Map<number, number> = new Map()
	constructor(filename: string, index: number) {
		this.filename = filename;
		this.index = index;
	}
	readFile() {
		const s = fs.readFileSync(this.filename, 'utf8')
		this.rows = s.split('\n').map(line => line.split(','));
	}
	extractMembers() {
		this.members = this.rows.map(row => Number(row[this.index]));
	}
	countMembers() {
		this.histogram = new Map()
		for (const m of this.members) {
			this.histogram.set(m, (this.histogram.get(m) || 0) + 1);
		}
	}
	printHistogram() {
		for (const [m, c] of Array.from(this.histogram)) {
			console.log(`${m}: ${'#'.repeat(c)}`);
		}
	}
+	run() {
+		this.readFile();
+		this.extractMembers()
+		this.countMembers()
+		this.printHistogram()
+	}
}

- new Histogram('input.csv', 0);
+ const histogram = new Histogram('input.csv', 0);
+ histogram.run();