js2flowchart/src/render/svg/svgObjectsBuilder.js

> Why? While I've been working on [Under-the-hood-ReactJS](https://github.com/Bogdan-Lyashenko/Under-the-hood-ReactJS) I spent enormous amount of time on creating schemes. Each change in code or flowchart affects all entire scheme instantly, forcing you t

import { complexTraversal } from 'shared/utils/traversalWithTreeLevelsPointer';
import { SVGBase } from './SVGBase';
import { createShapeForNode, createRootCircle, createConnectionArrow } from './shapesFactory';
import { TOKEN_TYPES, TOKEN_KEYS, ARROW_TYPE } from 'shared/constants';

export const buildSVGObjectsTree = (flowTree, styleTheme) => {
    const svg = SVGBase();

    const shapeStructures = buildShapeStructures(flowTree, styleTheme);
    const connections = buildConnections(shapeStructures.root, styleTheme);

    svg.addShapes(shapeStructures.list).addShapes(shapeStructures.root);
    svg.addArrowConnections(connections);

    return svg;
};

export const buildShapeStructures = (flowTree, styleTheme) => {
    const root = createRootCircle(flowTree, styleTheme),
        position = { ...root.getChildOffsetPoint() },
        shapesList = [];

    let latestNode;

    complexTraversal(
        flowTree,
        root,
        (parentNode, parentShape) => {
            position.x += parentShape.getChildOffsetPoint().x;
        },
        (node, parentShape) => {
            position.y += addExtraSpacingBeforeShape(styleTheme, node, latestNode);

            //TODO: refactor, move cases out of func, it will to many of them soon
            if (
                parentShape.getNodeType() === TOKEN_TYPES.CONDITIONAL &&
                node.key === TOKEN_KEYS.ALTERNATE &&
                !parentShape.checkIfChildExist(TOKEN_KEYS.ALTERNATE)
            ) {
                const alternatePoint = parentShape.getAlternativeBranchChildOffsetPoint();
                position.x = alternatePoint.x + parentShape.getMargin();
                position.y = alternatePoint.y;
            }

            const shape = createShapeForNode(node, { x: position.x, y: position.y }, styleTheme);

            position.x = shape.getPosition().x;
            position.y = shape.getPosition().y;

            shapesList.push(shape);
            parentShape.connectChild(shape);
            position.y += shape.getChildOffsetPoint().y;

            latestNode = node;
            return shape;
        },
        (parentNode, parentShape) => {
            if (parentNode.type === TOKEN_TYPES.CONDITIONAL) {
                position.y = parentShape.getChildBoundaries().max.y + parentShape.getMargin();
            }

            position.x = parentShape.getPosition().x;
        }
    );

    return {
        list: shapesList,
        root: root
    };
};

const addExtraSpacingBeforeShape = (theme, node, latestNode = {}) => {
    const complexNodeTypes = [
        TOKEN_TYPES.FUNCTION,
        TOKEN_TYPES.FUNCTION_DECLARATION,
        TOKEN_TYPES.FUNCTION_EXPRESSION,
        TOKEN_TYPES.ARROW_FUNCTION_EXPRESSION,
        TOKEN_TYPES.CLASS_DECLARATION,
        TOKEN_TYPES.IMPORT_DECLARATION,
        TOKEN_TYPES.EXPORT_NAMED_DECLARATION,
        TOKEN_TYPES.EXPORT_DEFAULT_DECLARATION
    ];

    if (
        complexNodeTypes.includes(node.type) &&
        !complexNodeTypes.includes(latestNode.type) &&
        node.pathParentType !== TOKEN_TYPES.CALL_EXPRESSION
    ) {
        return theme.BaseShape.complexTypeExtraSpace;
    }

    return 0;
};

export const buildConnections = (shapesTree, styleTheme) => {
    const connections = [],
        pushArrow = config => {
            const connection = createConnectionArrow(config, styleTheme);
            connections.push(connection);

            return connection;
        };

    let latestShape = null,
        latestParentShape = null;

    complexTraversal(
        shapesTree,
        shapesTree,
        parentShape => {},
        (shape, parentShape) => {
            latestShape = shape;

            const config = buildConnectionConfig(shape, parentShape),
                arrow = pushArrow(config);

            shape.assignConnectionArrow(arrow);

            return shape;
        },
        parentShape => {
            latestParentShape = parentShape;
            if (parentShape.getNodeType() !== TOKEN_TYPES.LOOP) return;

            const { max } = parentShape.getChildBoundaries();

            parentShape.assignLoopedConnectionArrow(
                pushArrow({
                    startPoint: latestShape.getBackPoint(),
                    endPoint: parentShape.getMidPoint(),
                    boundaryPoint: { x: max.x },
                    arrowType: ARROW_TYPE.DOWN
                })
            );
        },
        {
            getBody: node => node.getBody()
        }
    );

    return connections;
};

const isNoArrow = (toShape, fromShape) => {
    if (
        [
            TOKEN_TYPES.IMPORT_SPECIFIER,
            TOKEN_TYPES.IMPORT_DEFAULT_SPECIFIER,
            TOKEN_TYPES.OBJECT_PROPERTY
        ].includes(toShape.getNodeType())
    ) {
        return true;
    }

    if (
        [
            TOKEN_TYPES.FUNCTION_DECLARATION,
            TOKEN_TYPES.FUNCTION_EXPRESSION,
            TOKEN_TYPES.FUNCTION,
            TOKEN_TYPES.ARROW_FUNCTION_EXPRESSION
        ].includes(toShape.getNodeType()) &&
        [
            TOKEN_TYPES.CALL_EXPRESSION,
            TOKEN_TYPES.VARIABLE_DECLARATOR,
            TOKEN_TYPES.ASSIGNMENT_EXPRESSION,
            TOKEN_TYPES.NEW_EXPRESSION
        ].includes(fromShape.getNodeType())
    ) {
        return true;
    }
};

const buildConnectionConfig = (toShape, fromShape) => {
    const config = {
        endPoint: toShape.getToPoint(),
        arrowType: ARROW_TYPE.RIGHT,
        noArrow: isNoArrow(toShape, fromShape)
    };

    if (
        toShape.getNodeKey() === TOKEN_KEYS.ALTERNATE &&
        fromShape.getAlternativeBranchChildOffsetPoint
    ) {
        const boundaryPoint = fromShape.getAlternativeBranchChildOffsetPoint();

        config.startPoint = fromShape.getAlternateFromPoint();
        config.boundaryPoint = { x: boundaryPoint.x };
    } else {
        config.startPoint = fromShape.getFromPoint();
    }

    return config;
};