@nodesecure/js-x-ray/dist/NodeCounter.js

JavaScript AST XRay analysis

// Import Third-party Dependencies
import FrequencySet from "frequency-set";
// Import Internal Dependencies
import { isNode } from "./estree/types.js";
function noop() {
    return true;
}
export class NodeCounter {
    type;
    name;
    lookup = null;
    #count = 0;
    #properties = null;
    #filterFn = noop;
    #matchFn = noop;
    /**
     * @example
     * new NodeCounter("FunctionDeclaration");
     * new NodeCounter("VariableDeclaration[kind]");
     */
    constructor(type, options = {}) {
        if (typeof type !== "string") {
            throw new TypeError("type must be a string");
        }
        const typeResult = /([A-Za-z]+)(\[[a-zA-Z]+\])?/g.exec(type);
        if (typeResult === null) {
            throw new Error("invalid type argument syntax");
        }
        this.type = typeResult[1];
        this.lookup = typeResult[2]?.slice(1, -1) ?? null;
        this.name = options?.name ?? this.type;
        if (this.lookup) {
            this.#properties = new FrequencySet();
        }
        this.#filterFn = options.filter ?? noop;
        this.#matchFn = options.match ?? noop;
    }
    get count() {
        return this.#count;
    }
    get properties() {
        return Object.fromEntries(this.#properties?.entries() ?? []);
    }
    walk(node) {
        if (!isNode(node) || node.type !== this.type) {
            return;
        }
        const castedNode = node;
        if (!this.#filterFn(castedNode)) {
            return;
        }
        this.#count++;
        if (this.lookup === null) {
            this.#matchFn(castedNode, this);
        }
        else if (this.lookup in node) {
            this.#properties?.add(node[this.lookup]);
            this.#matchFn(castedNode, this);
        }
    }
}
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