max-dependencies.js

import isStaticRequire from '../core/staticRequire'
import docsUrl from '../docsUrl'

const DEFAULT_MAX = 10

const countDependencies = (dependencies, lastNode, context) => {
  const {max} = context.options[0] || { max: DEFAULT_MAX }

  if (dependencies.size > max) {
    context.report(
      lastNode,
      `Maximum number of dependencies (${max}) exceeded.`
    )
  }
}

module.exports = {
  meta: {
    type: 'suggestion',
    docs: {
      url: docsUrl('max-dependencies'),
    },

    schema: [
      {
        'type': 'object',
        'properties': {
          'max': { 'type': 'number' },
        },
        'additionalProperties': false,
      },
    ],
  },

  create: context => {
    const dependencies = new Set() // keep track of dependencies
    let lastNode // keep track of the last node to report on

    return {
      ImportDeclaration(node) {
        dependencies.add(node.source.value)
        lastNode = node.source
      },

      CallExpression(node) {
        if (isStaticRequire(node)) {
          const [ requirePath ] = node.arguments
          dependencies.add(requirePath.value)
          lastNode = node
        }
      },

      'Program:exit': function () {
        countDependencies(dependencies, lastNode, context)
      },
    }
  },
}