Code coverage report for src/hidden-node-appender/NodeAppender.ts

# All files / src/hidden-node-appender NodeAppender.ts

94.44% Statements 17/18
93.75% Branches 15/16
100% Functions 0/0
94.44% Lines 17/18

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     import * as ESTree from 'estree';

    import { TNodeWithBlockStatement } from '../types/TNodeWithBlockStatement';

    import { IBlockScopeTraceData } from '../interfaces/IBlockScopeTraceData';

    import { ASTTreeBlockScopeAnalyzer } from './ASTTreeBlockScopeAnalyzer';
    import { NodeUtils } from '../NodeUtils';
    import { Utils } from '../Utils';

    /**
     * This class appends node into a first deepest BlockStatement in order of function calls
     *
     * For example:
     *
     * function Foo () {
     *     var baz = function () {
     *
     *     }
     *
     *     baz();
     * }
     *
     * foo();
     *
     * Appends node into block statement of `baz` function expression.
     */
    export class HiddenNodeAppender {
        /**
         * @param blockScopeBody
         * @param node
         * @param index
         */
        public static appendNode (blockScopeBody: ESTree.Node[], node: ESTree.Node, index: number = 0): void {
            const blockScopeTraceData: IBlockScopeTraceData[] = new ASTTreeBlockScopeAnalyzer<IBlockScopeTraceData>(blockScopeBody).analyze();

            if (!blockScopeTraceData.length) {
                NodeUtils.prependNode(blockScopeBody, node);

                return;
            }

            NodeUtils.prependNode(
                HiddenNodeAppender.getOptimalBlockScope(blockScopeTraceData, index).body,
                node
            );
        }

        /**
         * @param blockStatementBodyLength
         * @param threshold
         */
        public static getIndexByThreshold (blockStatementBodyLength: number, threshold: number = 0.1): number {
            Iif (threshold < 0 || threshold > 1) {
                throw new RangeError('`threshold` parameter should has value between 0 and 1');
            }

            return Utils.getRandomGenerator().integer({
                min: 0,
                max: Math.round(blockStatementBodyLength * threshold)
            });
        }

        /**
         * @param blockScopeTraceData
         * @param index
         * @returns {TNodeWithBlockStatement}
         */
        private static getOptimalBlockScope (blockScopeTraceData: IBlockScopeTraceData[], index: number): TNodeWithBlockStatement {
            const firstCall: IBlockScopeTraceData = blockScopeTraceData[index];

            if (firstCall.trace.length) {
                return HiddenNodeAppender.getOptimalBlockScope(firstCall.trace, 0);
            } else {
                return firstCall.callee;
            }
        }
    }