• Accepts base-summary.json and head-summary.json
• Diffs the two jsons and outputs info about
  • Percentage of changed coverage (in changed/added files)
  • Formatted as markdown table
• Fail if coverage decreases on a file (check on percentage) for any of the lines/func/statements/branches. Can  be configured to only check some criteria.
• Written in Typescript

const fs = require('fs');
const coverageDiff = require('coverage-diff');

const base = JSON.parse(fs.readFileSync('./base-summary.json'));
const head = JSON.parse(fs.readFileSync('./head-summary.json'));
const diff = coverageDiff.diff(base, head);

console.log(diff.diff);
console.log(diff.results);
console.log(diff.regression);

Out:

API at https://flaviusone.github.io/coverage-diff/globals.html#diff

https://flaviusone.github.io/coverage-diff/