javascript-obfuscator/src/node-transformers/converting-transformers/NumberToNumericalExpressionTransformer.ts

import { inject, injectable, } from 'inversify';
import { ServiceIdentifiers } from '../../container/ServiceIdentifiers';

import * as ESTree from 'estree';

import { TNumberNumericalExpressionData } from '../../types/analyzers/number-numerical-expression-analyzer/TNumberNumericalExpressionData';

import { INumberNumericalExpressionAnalyzer } from '../../interfaces/analyzers/number-numerical-expression-analyzer/INumberNumericalExpressionAnalyzer';
import { IOptions } from '../../interfaces/options/IOptions';
import { IRandomGenerator } from '../../interfaces/utils/IRandomGenerator';
import { IVisitor } from '../../interfaces/node-transformers/IVisitor';

import { NodeTransformationStage } from '../../enums/node-transformers/NodeTransformationStage';

import { AbstractNodeTransformer } from '../AbstractNodeTransformer';
import { NodeGuards } from '../../node/NodeGuards';
import { NodeFactory } from '../../node/NodeFactory';
import { NumberNumericalExpressionAnalyzer } from '../../analyzers/number-numerical-expression-analyzer/NumberNumericalExpressionAnalyzer';
import { NumberUtils } from '../../utils/NumberUtils';
import { NumericalExpressionDataToNodeConverter } from '../../node/NumericalExpressionDataToNodeConverter';

/**
 * replaces:
 *     var number = 123;
 *
 * on:
 *     var number = 50 + (100 * 2) - 127;
 */
@injectable()
export class NumberToNumericalExpressionTransformer extends AbstractNodeTransformer {
    /**
     * @type {INumberNumericalExpressionAnalyzer}
     */
    private readonly numberNumericalExpressionAnalyzer: INumberNumericalExpressionAnalyzer;

    /**
     * @param {INumberNumericalExpressionAnalyzer} numberNumericalExpressionAnalyzer
     * @param {IRandomGenerator} randomGenerator
     * @param {IOptions} options
     */
    public constructor (
        @inject(ServiceIdentifiers.INumberNumericalExpressionAnalyzer)
            numberNumericalExpressionAnalyzer: INumberNumericalExpressionAnalyzer,
        @inject(ServiceIdentifiers.IRandomGenerator) randomGenerator: IRandomGenerator,
        @inject(ServiceIdentifiers.IOptions) options: IOptions
    ) {
        super(randomGenerator, options);

        this.numberNumericalExpressionAnalyzer = numberNumericalExpressionAnalyzer;
    }

    /**
     * @param {NodeTransformationStage} nodeTransformationStage
     * @returns {IVisitor | null}
     */
    public getVisitor (nodeTransformationStage: NodeTransformationStage): IVisitor | null {
        if (!this.options.numbersToExpressions) {
            return null;
        }

        switch (nodeTransformationStage) {
            case NodeTransformationStage.Converting:
                return {
                    leave: (node: ESTree.Node, parentNode: ESTree.Node | null): ESTree.Node | undefined => {
                        if (parentNode && NodeGuards.isLiteralNode(node)) {
                            return this.transformNode(node, parentNode);
                        }
                    }
                };

            default:
                return null;
        }
    }

    /**
     * @param {Literal} literalNode
     * @param {NodeGuards} parentNode
     * @returns {NodeGuards}
     */
    public transformNode (literalNode: ESTree.Literal, parentNode: ESTree.Node): ESTree.Node {
        if (typeof literalNode.value !== 'number') {
            return literalNode;
        }

        if (NodeGuards.isPropertyNode(parentNode) && !parentNode.computed) {
            return literalNode;
        }

        const baseNumber: number = literalNode.value;
        const [integerPart, decimalPart] = NumberUtils.extractIntegerAndDecimalParts(baseNumber);
        const integerNumberNumericalExpressionData: TNumberNumericalExpressionData = this.numberNumericalExpressionAnalyzer
            .analyze(
                integerPart,
                NumberNumericalExpressionAnalyzer.defaultAdditionalPartsCount
            );

        if (decimalPart) {
            return NumericalExpressionDataToNodeConverter.convertFloatNumberData(
                integerNumberNumericalExpressionData,
                decimalPart,
                this.getNumberNumericalExpressionLiteralNode
            );
        } else {
            return NumericalExpressionDataToNodeConverter.convertIntegerNumberData(
                integerNumberNumericalExpressionData,
                this.getNumberNumericalExpressionLiteralNode
            );
        }
    }

    /**
     * @param {number} number
     * @param {boolean} isPositiveNumber
     * @returns {Expression}
     */
    private getNumberNumericalExpressionLiteralNode (number: number, isPositiveNumber: boolean): ESTree.Expression {
        const numberLiteralNode: ESTree.Literal = NodeFactory.literalNode(number);

        return isPositiveNumber
            ? numberLiteralNode
            : NodeFactory.unaryExpressionNode(
                '-',
                numberLiteralNode
            );
    }
}