NIFI-15704 - Upgrade eslint from 8 to 10

[rfellows]

Summary

NIFI-15704

Description

Upgrades the NiFi frontend Nx workspace (nifi-frontend/src/main/frontend) from ESLint 8 to ESLint 10 and migrates all project-level configuration from legacy .eslintrc.json to the flat config format (eslint.config.mjs). This aligns the toolchain with current ESLint releases.

The upgrade required dependency updates (notably @typescript-eslint/* and Prettier-related ESLint packages), Nx cache input updates, and a set of source fixes so lint completes with zero errors and zero warnings across all six frontend projects: nifi, nifi-registry, nifi-jolt-transform-ui, standard-content-viewer, update-attribute, and shared.

The largest functional code changes are in flow-designer D3 services: removal of the const self = this / function callback pattern in favor of arrow functions and explicit element access, which satisfies @typescript-eslint/no-this-alias without suppressing the rule.

What's Changed

Tooling and configuration

• Bump eslint from 8.57.0 to ^10.0.3 and refresh eslint-config-prettier / eslint-plugin-prettier
• Bump @typescript-eslint/eslint-plugin, @typescript-eslint/parser, and @typescript-eslint/utils from 7.18.0 to 8.57.1; add typescript-eslint (^8.40.0)
• Add @eslint/eslintrc, @eslint/js, and globals for flat config, recommended presets, Jest globals, and FlatCompat bridging of legacy extends chains
• Remove package.json overrides entry for @humanwhocodes/config-array / minimatch (no longer needed with ESLint 10's dependency tree)
• Adjust engines.node to ^20.19.0 || ^22.13.0 || >=24.0.0 to match ESLint 10's engine requirements

Flat config migration

• Delete workspace root .eslintrc.json and add root eslint.config.mjs using FlatCompat, @eslint/js, @nx/eslint-plugin, Nx module boundary rules, compat.config({ extends: ['plugin:@nx/typescript' | 'plugin:@nx/javascript'] }) with file globs, and Jest globals for *.spec.* via globals.jest
• Replace each app/library .eslintrc.json with eslint.config.mjs (same rule intent: @nx/angular, recommended sets, Angular ESLint, Prettier; project-specific selector and relaxation rules preserved; no-unused-vars configured with _ ignore patterns including caughtErrorsIgnorePattern)
• Update nx.json so @nx/eslint:lint cache inputs and production filesets reference eslint.config.mjs instead of .eslintrc.json

Application / library source fixes

• D3 / flow-designer: Refactor behavior and manager services (connectable-behavior, draggable-behavior, quick-select-behavior, selectable-behavior, birdseye-view, canvas-view, canvas-utils, connection-manager, label-manager, port-manager, process-group-manager, remote-process-group-manager) to avoid no-this-alias: use arrow callbacks, .each((_d, i, nodes) => …) with nodes[i], .on('click', (event) => …) with event.currentTarget, and d3.drag().subject(function (this: Element) { return { element: this }; }) so drag handlers can use event.subject.element
• TypeScript ESLint 8: Replace empty marker interfaces with type aliases where required (*Definition state types)
• Unused bindings: Prefix unused catch parameters with _ (app.module.ts, registry-auth.service.ts, shared storage services)
• Sort comparators: Use let retVal: number instead of initializing to 0 where the first branch assigns, to avoid no-unused-vars on the initializer (multiple table components)
• Specs / small fixes: Minor test and component adjustments (content-viewer, standard-content-viewer, flow-status, user-access-policies, shared Codemirror spec) for lint cleanliness

Testing / Verification

• nx run-many -t lint for all 6 projects — 0 errors, 0 warnings

Screenshots

Not applicable (tooling and non-visual refactors).

[mcgilman]

Reviewing...

[mcgilman]

Thanks for the updates @rfellows!