npm-template-sync/src/merge-and-remove-line-set.mjs

Keep npm package in sync with its template

import { MergeLineSet } from "./merge-line-set.mjs";

/**
 *
 */
export class MergeAndRemoveLineSet extends MergeLineSet {
  async mergeContent(context, original, template) {
    const toBeRemoved = new Set([
      "",
      ...template
        .split(/\r?\n/)
        .filter(l => l.startsWith("- "))
        .map(l => l.replace(/^-\s+/, "")),
      ...Array.from(this.defaultIgnoreSet)
    ]);

    const result = new Set(
      template.split(/\r?\n/).filter(l => !l.match(/^-\s+/))
    );
    original
      .split(/\r?\n/)
      .filter(l => !toBeRemoved.has(l))
      .forEach(line => result.add(line));

    const content = Array.from(result.values()).join("\n");

    return {
      content,
      changed: content !== original,
      messages: [
        this.options.message ||
          "chore: update {{entry.name}} updated from template"
      ]
    };
  }
}