ts-budgie/src/nodes/visitors/propertyAccess/arrayMemberFunctionChecker.ts

Converts TypeScript code to Budgie.

import { CommandNames } from "budgie";
import * as ts from "typescript";

import { BudgieLine } from "../../../output/budgieLine";
import { Transformation } from "../../../output/transformation";

import { PropertyAccessChecker } from "./propertyAccessChecker";

interface IKnownMethodInfo {
    argsCount: number;
    commandName: string;
}

const knownMethodPairs = new Map<string, IKnownMethodInfo>([
    [
        "concat",
        {
            argsCount: 1,
            commandName: CommandNames.ListAddList,
        },
    ],
    [
        "pop",
        {
            argsCount: 0,
            commandName: CommandNames.ListPop,
        },
    ],
    [
        "unshift",
        {
            argsCount: 0,
            commandName: CommandNames.ListPopFront,
        },
    ],
    [
        "push",
        {
            argsCount: 1,
            commandName: CommandNames.ListPush,
        },
    ],
]);

export class ArrayMemberFunctionChecker extends PropertyAccessChecker {
    public visit(node: ts.PropertyAccessExpression): Transformation[] | undefined {
        if (node.parent === undefined || !ts.isCallExpression(node.parent) || !this.isArray(node.expression)) {
            return undefined;
        }

        const nativeMethodName = node.name.getText(this.sourceFile);
        const budgieMethodPairing = knownMethodPairs.get(nativeMethodName);
        if (budgieMethodPairing === undefined || node.parent.arguments.length !== budgieMethodPairing.argsCount) {
            return undefined;
        }

        const expression = this.router.recurseIntoValue(node.expression);
        const args = this.router.recurseIntoValues(node.parent.arguments);

        return [Transformation.fromNode(node, this.sourceFile, [new BudgieLine(budgieMethodPairing.commandName, expression, ...args)])];
    }

    private isArray(expression: ts.Expression) {
        const symbol = this.typeChecker.getSymbolAtLocation(expression);
        if (symbol === undefined || symbol.declarations === undefined) {
            return false;
        }

        const [declaration] = symbol.declarations;
        const friendlyTypeName = this.aliaser.getFriendlyTypeName(declaration);
        if (friendlyTypeName === undefined || typeof friendlyTypeName === "string") {
            return false;
        }

        return friendlyTypeName.command === CommandNames.ListType;
    }
}