no-spaces-around-equal-signs-in-attribute.ts

import { createRule } from "../utils"
import type { AST } from "svelte-eslint-parser"

export default createRule("no-spaces-around-equal-signs-in-attribute", {
  meta: {
    docs: {
      description: "disallow spaces around equal signs in attribute",
      category: "Stylistic Issues",
      recommended: false,
      conflictWithPrettier: true,
    },
    schema: {},
    fixable: "whitespace",
    messages: {
      noSpaces: "Unexpected spaces found around equal signs.",
    },
    type: "layout",
  },
  create(ctx) {
    const source = ctx.getSourceCode()

    /**
     * Returns source text between attribute key and value, and range of that source
     */
    function getAttrEq(
      node:
        | AST.SvelteAttribute
        | AST.SvelteDirective
        | AST.SvelteStyleDirective
        | AST.SvelteSpecialDirective,
    ): [string, AST.Range] {
      const keyRange = node.key.range
      const eqSource = /^[\s=]*/u.exec(
        source.text.slice(keyRange[1], node.range[1]),
      )![0]
      const valueStart = keyRange[1] + eqSource.length
      return [eqSource, [keyRange[1], valueStart]]
    }

    /**
     * Returns true if string contains whitespace characters
     */
    function containsWhitespace(string: string): boolean {
      return /\s/u.test(string)
    }

    return {
      "SvelteAttribute, SvelteDirective, SvelteStyleDirective, SvelteSpecialDirective"(
        node:
          | AST.SvelteAttribute
          | AST.SvelteDirective
          | AST.SvelteStyleDirective
          | AST.SvelteSpecialDirective,
      ) {
        const [eqSource, range] = getAttrEq(node)

        if (!containsWhitespace(eqSource)) return

        const loc = {
          start: source.getLocFromIndex(range[0]),
          end: source.getLocFromIndex(range[1]),
        }

        ctx.report({
          loc,
          messageId: "noSpaces",
          *fix(fixer) {
            yield fixer.replaceTextRange(range, "=")
          },
        })
      },
    }
  },
})