@stryker-mutator/core/src/mutants/diff-statistics-collector.ts

The extendable JavaScript mutation testing framework

import chalk from 'chalk';

export class DiffChanges {
  public added = 0;
  public removed = 0;
  public toString(): string {
    return `${chalk.greenBright(`+${this.added}`)} ${chalk.redBright(`-${this.removed}`)}`;
  }
}
export type DiffChange = 'added' | 'removed';

export class DiffStatisticsCollector {
  public readonly changesByFile = new Map<string, DiffChanges>();
  public readonly total = new DiffChanges();

  public count(file: string, change: DiffChange, amount = 1): void {
    if (amount === 0) {
      // Nothing to see here
      return;
    }
    let changes = this.changesByFile.get(file);
    if (!changes) {
      changes = new DiffChanges();
      this.changesByFile.set(file, changes);
    }
    switch (change) {
      case 'added':
        changes.added += amount;
        this.total.added += amount;
        break;
      case 'removed':
        changes.removed += amount;
        this.total.removed += amount;
        break;
    }
  }

  public createDetailedReport(): string[] {
    return [...this.changesByFile.entries()].map(([fileName, changes]) => `${fileName} ${changes.toString()}`);
  }

  public createTotalsReport(): string {
    return `${chalk.yellowBright(this.changesByFile.size)} files changed (${this.total.toString()})`;
  }
}