prefer-d.ts

import type {
    CharacterClass,
    CharacterClassElement,
    CharacterClassRange,
    EscapeCharacterSet,
    ExpressionCharacterClass,
} from "@eslint-community/regexpp/ast"
import type { RegExpVisitor } from "@eslint-community/regexpp/visitor"
import { Chars, toUnicodeSet } from "regexp-ast-analysis"
import type { RegExpContext } from "../utils"
import {
    createRule,
    defineRegexpVisitor,
    CP_DIGIT_ZERO,
    CP_DIGIT_NINE,
} from "../utils"
import { mention } from "../utils/mention"

/**
 * Returns whether the given character class element is equivalent to `\d`.
 */
function isDigits(
    element: CharacterClassElement,
): element is EscapeCharacterSet | CharacterClassRange {
    return (
        (element.type === "CharacterSet" &&
            element.kind === "digit" &&
            !element.negate) ||
        (element.type === "CharacterClassRange" &&
            element.min.value === CP_DIGIT_ZERO &&
            element.max.value === CP_DIGIT_NINE)
    )
}

export default createRule("prefer-d", {
    meta: {
        docs: {
            description: "enforce using `\\d`",
            category: "Stylistic Issues",
            recommended: true,
        },
        fixable: "code",
        schema: [
            {
                type: "object",
                properties: {
                    insideCharacterClass: {
                        type: "string",
                        enum: ["ignore", "range", "d"],
                    },
                },
                additionalProperties: false,
            },
        ],
        messages: {
            unexpected:
                "Unexpected {{type}} {{expr}}. Use '{{instead}}' instead.",
        },
        type: "suggestion",
    },
    create(context) {
        const insideCharacterClass: "ignore" | "range" | "d" =
            context.options[0]?.insideCharacterClass ?? "ignore"

        function createVisitor({
            node,
            flags,
            getRegexpLocation,
            fixReplaceNode,
        }: RegExpContext): RegExpVisitor.Handlers {
            function verifyCharacterClass(
                ccNode: CharacterClass | ExpressionCharacterClass,
            ) {
                const charSet = toUnicodeSet(ccNode, flags)

                let predefined: string | undefined = undefined
                if (charSet.equals(Chars.digit(flags))) {
                    predefined = "\\d"
                } else if (charSet.equals(Chars.digit(flags).negate())) {
                    predefined = "\\D"
                }

                if (predefined) {
                    context.report({
                        node,
                        loc: getRegexpLocation(ccNode),
                        messageId: "unexpected",
                        data: {
                            type: "character class",
                            expr: mention(ccNode),
                            instead: predefined,
                        },
                        fix: fixReplaceNode(ccNode, predefined),
                    })
                    return
                }

                if (
                    insideCharacterClass === "ignore" ||
                    ccNode.type !== "CharacterClass"
                ) {
                    return
                }

                const expected = insideCharacterClass === "d" ? "\\d" : "0-9"

                // check the elements in this character class
                for (const e of ccNode.elements) {
                    if (isDigits(e) && e.raw !== expected) {
                        context.report({
                            node,
                            loc: getRegexpLocation(e),
                            messageId: "unexpected",
                            data: {
                                type:
                                    e.type === "CharacterSet"
                                        ? "character set"
                                        : "character class range",
                                expr: mention(e),
                                instead: expected,
                            },
                            fix: fixReplaceNode(e, expected),
                        })
                    }
                }
            }

            return {
                onCharacterClassEnter: verifyCharacterClass,
                onExpressionCharacterClassEnter: verifyCharacterClass,
            }
        }

        return defineRegexpVisitor(context, {
            createVisitor,
        })
    },
})