Eslint/Updates (and drop Gulp)

[brettz9]

A few disclaimers:

1. This has not yet been manually tested to ensure builds still working with older versions.
2. I'm also not fully sure whether my browserify script replacement for the gulp file works as intended, but I've set it as standalone so it could be used as is (if you are ok with Rollup, I could add that in its place, getting an ESM distribution in the process as well). I've added Rollup
3. I didn't replace the bump functionality from the gulp file (the only remaining item which was not ported). I see there is a CLI option if you wanted me to add that: https://www.npmjs.com/package/npm-bump
4. I temporarily set the nyc thresholds to pass as is, so we could see if the builds otherwise pass Travis, though I presume you will want to change that, especially after may get to 100% coverage.

• Breaking change: Remove deprecated bower
• Linting: Remove old jslint directive; remove jshintrc
• Linting: Move ESLint to npm script
• Linting: Remove deprecated ecmaFeatures from config
• Linting: Apply automated fixes (e.g., prefer-const) and manual fixes per config (e.g., prefer-destructuring) and moving const/let closer to necessary scope
• Travis: Drop pre Node 10 versions and add Node 10 and 12
• npm: Remove gulpfile in place of npm scripts, including Mocha and Babel building/watch
• npm: Provide tentative browserify script
• npm: add bugs and keywords; use package.json linter-recognized author/contributors over maintainers
• npm: Add .npmrc to avoid package-lock.json
• npm: Use rollup/plugin-babel over deprecated rollup-plugin-babel
• npm: Switch to non-deprecated @babel/preset-env and to Babel 7
• npm: Update deps. (esrecurse, estraverse (major bump)) and devDeps.
• Update: Switch from local copy to npm package for esprima
• Babel: Switch to use "json" extension
• Babel: With preset-env, target Node 4+ for Babel (to avoid needing to polyfill features only needed in earlier versions)
• Maintenance: Add .editorconfig
• Testing: Fix es6-destructuring-assignments.js check of rest element per updated Esprima
• Testing: Fix esprima import syntax
• Testing: Update export tests to avoid error with exported variable not being defined
• Testing: Add nyc, setting coverage for now to pass as is (i.e., not at 100% thresholds)

[michaelficarra]

Can't we replace the bump script with https://docs.npmjs.com/cli-commands/version.html?

[brettz9]

Yes, I think so, depending on how you want it configured I guess. Do you want npm scripts for each bump type or do you just want to use these on your own? I have a feeling this is more the kind of thing you might want to tweak to your liking. I think the only thing of probable relevance from the Gulpfile removal is just that the commit message had been "Bumps package version" if you wish to keep it consistent.

[michaelficarra]

Yeah I don't really care about commit message consistency.

Do you want npm scripts for each bump type or do you just want to use these on your own?

That seems a bit unnecessary.

[brettz9]

Ok, I guess that's all you need from me for now then?

Btw, off topic, and no worries if there is no interest, but wanted to offer https://github.com/brettz9/es-file-traverse for your consideration for inclusion on estools, as I think it fills a basic need and should be relevant to the organization.

[brettz9]

Think you can find time to review?