eslint-plugin-vue/lib/rules/return-in-computed-property.js

Official ESLint plugin for Vue.js

/**
 * @fileoverview Enforces that a return statement is present in computed property (return-in-computed-property)
 * @author Armano
 */
'use strict'
const { ReferenceTracker } = require('@eslint-community/eslint-utils')
const utils = require('../utils')

/**
 * @typedef {import('../utils').ComponentComputedProperty} ComponentComputedProperty
 */

module.exports = {
  meta: {
    type: 'problem',
    docs: {
      description:
        'enforce that a return statement is present in computed property',
      categories: ['vue3-essential', 'vue2-essential'],
      url: 'https://eslint.vuejs.org/rules/return-in-computed-property.html'
    },
    fixable: null,
    schema: [
      {
        type: 'object',
        properties: {
          treatUndefinedAsUnspecified: {
            type: 'boolean'
          }
        },
        additionalProperties: false
      }
    ],
    messages: {
      expectedReturnInFunction:
        'Expected to return a value in computed function.',
      expectedReturnInProperty:
        'Expected to return a value in "{{name}}" computed property.'
    }
  },
  /** @param {RuleContext} context */
  create(context) {
    const options = context.options[0] || {}
    const treatUndefinedAsUnspecified = !(
      options.treatUndefinedAsUnspecified === false
    )

    /**
     * @type {Set<ComponentComputedProperty>}
     */
    const computedProperties = new Set()
    /** @type {(FunctionExpression | ArrowFunctionExpression)[]} */
    const computedFunctionNodes = []

    return Object.assign(
      {
        /** @param {Program} program */
        Program(program) {
          const tracker = new ReferenceTracker(utils.getScope(context, program))
          const map = {
            computed: {
              [ReferenceTracker.CALL]: true
            }
          }

          for (const { node } of utils.iterateReferencesTraceMap(
            tracker,
            map
          )) {
            if (node.type !== 'CallExpression') {
              continue
            }

            const getter = utils.getGetterBodyFromComputedFunction(node)
            if (getter) {
              computedFunctionNodes.push(getter)
            }
          }
        }
      },
      utils.defineVueVisitor(context, {
        onVueObjectEnter(obj) {
          for (const computedProperty of utils.getComputedProperties(obj)) {
            computedProperties.add(computedProperty)
          }
        }
      }),
      utils.executeOnFunctionsWithoutReturn(
        treatUndefinedAsUnspecified,
        (node) => {
          for (const cp of computedProperties) {
            if (cp.value && cp.value.parent === node) {
              context.report({
                node,
                messageId: 'expectedReturnInProperty',
                data: {
                  name: cp.key || 'Unknown'
                }
              })
            }
          }
          for (const cf of computedFunctionNodes) {
            if (cf === node) {
              context.report({
                node,
                messageId: 'expectedReturnInFunction'
              })
            }
          }
        }
      )
    )
  }
}