noob-components/packages/base/data/json-view/flattenJson.ts

import type { BuildVisibleJsonRowsOptions, JsonViewNode, JsonViewNodeType } from "./types";

type PlainObject = Record<string, unknown>;
type JsonContainerKind = "object" | "array" | "map" | "set";
type JsonContainerValue = PlainObject | unknown[] | Map<unknown, unknown> | Set<unknown>;

interface RowContext {
  path: string;
  level: number;
  key?: string;
  displayKey?: string;
  keyValue?: unknown;
  index?: number;
  showComma: boolean;
  posInSet: number;
  setSize: number;
}

interface LineCounter {
  nextLineNumber: number;
}

function isRecordLike(value: unknown): value is Record<string, unknown> {
  return value !== null && typeof value === "object" && !Array.isArray(value) && !(value instanceof Map) && !(value instanceof Set);
}

function buildNodeId(path: string, type: JsonViewNodeType) {
  return `${path}:${type}`;
}

function buildObjectPath(parentPath: string, key: string) {
  if (/^[A-Za-z_$][\w$]*$/.test(key)) {
    return `${parentPath}.${key}`;
  }
  return `${parentPath}[${JSON.stringify(key)}]`;
}

function buildArrayPath(parentPath: string, index: number) {
  return `${parentPath}[${index}]`;
}

function buildMapPath(parentPath: string, key: unknown, index: number) {
  if (typeof key === "string") {
    return `${parentPath}.get(${JSON.stringify(key)})`;
  }

  if (typeof key === "number" || typeof key === "boolean" || typeof key === "bigint") {
    return `${parentPath}.get(${String(key)})`;
  }

  if (key === null) {
    return `${parentPath}.get(null)`;
  }

  if (key === undefined) {
    return `${parentPath}.get(undefined)`;
  }

  if (typeof key === "symbol") {
    return `${parentPath}.get(${String(key)})`;
  }

  return `${parentPath}.entries[${index}]`;
}

function isCollapsedByDefault(level: number, length: number, options: BuildVisibleJsonRowsOptions) {
  const deepCollapsed = typeof options.deep === "number" ? level + 1 > options.deep : false;
  const lengthCollapsed =
    typeof options.collapsedNodeLength === "number" ? length > options.collapsedNodeLength : false;
  return deepCollapsed || lengthCollapsed;
}

function isExpanded(path: string, level: number, length: number, options: BuildVisibleJsonRowsOptions) {
  const explicit = options.expandedState.get(path);
  if (explicit !== undefined) {
    return explicit;
  }
  return !isCollapsedByDefault(level, length, options);
}

function formatKeyDisplay(value: unknown) {
  if (typeof value === "string") {
    return JSON.stringify(value);
  }
  if (typeof value === "number" || typeof value === "boolean") {
    return String(value);
  }
  if (typeof value === "bigint") {
    return `${String(value)}n`;
  }
  if (value === null) {
    return "null";
  }
  if (value === undefined) {
    return "undefined";
  }
  if (typeof value === "symbol") {
    return value.toString();
  }
  if (typeof value === "function") {
    return value.name ? `[Function ${value.name}]` : "[Function]";
  }
  if (Array.isArray(value)) {
    return `Array(${value.length})`;
  }
  if (value instanceof Map) {
    return `Map(${value.size})`;
  }
  if (value instanceof Set) {
    return `Set(${value.size})`;
  }
  return "Object";
}

function formatPrimitiveDisplay(value: unknown) {
  if (typeof value === "string") {
    return JSON.stringify(value);
  }
  if (typeof value === "number" || typeof value === "boolean") {
    return String(value);
  }
  if (typeof value === "bigint") {
    return `${String(value)}n`;
  }
  if (value === null) {
    return "null";
  }
  if (value === undefined) {
    return "undefined";
  }
  if (typeof value === "symbol") {
    return value.toString();
  }
  if (typeof value === "function") {
    return value.name ? `[Function ${value.name}]` : "[Function]";
  }
  return String(value);
}

function getContainerKind(value: unknown): JsonContainerKind | null {
  if (Array.isArray(value)) {
    return "array";
  }
  if (value instanceof Map) {
    return "map";
  }
  if (value instanceof Set) {
    return "set";
  }
  if (isRecordLike(value)) {
    return "object";
  }
  return null;
}

function getContainerLength(value: JsonContainerValue, kind: JsonContainerKind) {
  switch (kind) {
    case "array":
      return (value as unknown[]).length;
    case "map":
      return (value as Map<unknown, unknown>).size;
    case "set":
      return (value as Set<unknown>).size;
    case "object":
    default:
      return Object.keys(value as PlainObject).length;
  }
}

function getContainerContent(kind: JsonContainerKind, state: "start" | "end" | "collapsed") {
  switch (kind) {
    case "map":
      if (state === "start") return "Map {";
      if (state === "end") return "}";
      return "Map {...}";
    case "set":
      if (state === "start") return "Set [";
      if (state === "end") return "]";
      return "Set [...]";
    case "object":
      if (state === "start") return "{";
      if (state === "end") return "}";
      return "{...}";
    case "array":
    default:
      if (state === "start") return "[";
      if (state === "end") return "]";
      return "[...]";
  }
}

function getContainerNodeType(kind: JsonContainerKind, state: "start" | "end" | "collapsed"): JsonViewNodeType {
  if (kind === "object" || kind === "map") {
    if (state === "start") return "objectStart";
    if (state === "end") return "objectEnd";
    return "objectCollapsed";
  }

  if (state === "start") return "arrayStart";
  if (state === "end") return "arrayEnd";
  return "arrayCollapsed";
}

function countValueLines(value: unknown, ancestors = new WeakSet<object>()): number {
  const kind = getContainerKind(value);
  if (!kind) {
    return 1;
  }

  const reference = value as object;
  if (ancestors.has(reference)) {
    return 1;
  }

  ancestors.add(reference);

  const total =
    kind === "array"
      ? 2 + (value as unknown[]).reduce<number>((sum, entry) => sum + countValueLines(entry, ancestors), 0)
      : kind === "set"
        ? 2 + Array.from(value as Set<unknown>).reduce<number>((sum, entry) => sum + countValueLines(entry, ancestors), 0)
        : kind === "map"
          ? 2 +
            Array.from((value as Map<unknown, unknown>).values()).reduce<number>(
              (sum, entry) => sum + countValueLines(entry, ancestors),
              0
            )
          : 2 +
            Object.values(value as PlainObject).reduce<number>((sum, entry) => sum + countValueLines(entry, ancestors), 0);

  ancestors.delete(reference);
  return total;
}

function countContainerChildLines(kind: JsonContainerKind, value: JsonContainerValue, ancestors: WeakSet<object>) {
  if (kind === "array") {
    return (value as unknown[]).reduce<number>((sum, entry) => sum + countValueLines(entry, ancestors), 0);
  }

  if (kind === "set") {
    return Array.from(value as Set<unknown>).reduce<number>((sum, entry) => sum + countValueLines(entry, ancestors), 0);
  }

  if (kind === "map") {
    return Array.from((value as Map<unknown, unknown>).values()).reduce<number>(
      (sum, entry) => sum + countValueLines(entry, ancestors),
      0
    );
  }

  return Object.values(value as PlainObject).reduce<number>((sum, entry) => sum + countValueLines(entry, ancestors), 0);
}

function createNode(
  counter: LineCounter,
  context: RowContext,
  type: JsonViewNodeType,
  content: string,
  value: unknown,
  extras?: Partial<JsonViewNode>
): JsonViewNode {
  return {
    id: buildNodeId(context.path, type),
    path: context.path,
    lineNumber: counter.nextLineNumber++,
    level: context.level,
    key: context.key,
    displayKey: context.displayKey,
    keyValue: context.keyValue,
    index: context.index,
    content,
    showComma: context.showComma,
    type,
    value,
    isLeaf: type === "content",
    hasToggle: false,
    isExpanded: false,
    posInSet: context.posInSet,
    setSize: context.setSize,
    ...extras,
  };
}

function appendValueRows(
  value: unknown,
  context: RowContext,
  rows: JsonViewNode[],
  options: BuildVisibleJsonRowsOptions,
  counter: LineCounter,
  ancestors: WeakSet<object>
) {
  const kind = getContainerKind(value);
  if (!kind) {
    rows.push(createNode(counter, context, "content", formatPrimitiveDisplay(value), value, { isLeaf: true }));
    return;
  }

  const reference = value as object;
  if (ancestors.has(reference)) {
    rows.push(createNode(counter, context, "content", "[Circular]", value, { isLeaf: true }));
    return;
  }

  ancestors.add(reference);
  appendContainerRows(kind, value as JsonContainerValue, context, rows, options, counter, ancestors);
  ancestors.delete(reference);
}

function appendContainerRows(
  kind: JsonContainerKind,
  value: JsonContainerValue,
  context: RowContext,
  rows: JsonViewNode[],
  options: BuildVisibleJsonRowsOptions,
  counter: LineCounter,
  ancestors: WeakSet<object>
) {
  const length = getContainerLength(value, kind);
  const expanded = isExpanded(context.path, context.level, length, options);
  const totalLineCount = 2 + countContainerChildLines(kind, value, ancestors);

  if (!expanded) {
    rows.push(
      createNode(counter, context, getContainerNodeType(kind, "collapsed"), getContainerContent(kind, "collapsed"), value, {
        length,
        hasToggle: true,
        isExpanded: false,
        isLeaf: false,
      })
    );
    counter.nextLineNumber += totalLineCount - 1;
    return;
  }

  rows.push(
    createNode(counter, context, getContainerNodeType(kind, "start"), getContainerContent(kind, "start"), value, {
      length,
      hasToggle: true,
      isExpanded: true,
      isLeaf: false,
      showComma: false,
    })
  );

  if (kind === "object") {
    Object.entries(value as PlainObject).forEach(([key, childValue], index) => {
      appendValueRows(
        childValue,
        {
          path: buildObjectPath(context.path, key),
          level: context.level + 1,
          key,
          showComma: index < length - 1,
          posInSet: index + 1,
          setSize: length,
        },
        rows,
        options,
        counter,
        ancestors
      );
    });
  } else if (kind === "array") {
    (value as unknown[]).forEach((childValue, index) => {
      appendValueRows(
        childValue,
        {
          path: buildArrayPath(context.path, index),
          level: context.level + 1,
          index,
          showComma: index < length - 1,
          posInSet: index + 1,
          setSize: length,
        },
        rows,
        options,
        counter,
        ancestors
      );
    });
  } else if (kind === "set") {
    Array.from(value as Set<unknown>).forEach((childValue, index) => {
      appendValueRows(
        childValue,
        {
          path: buildArrayPath(context.path, index),
          level: context.level + 1,
          index,
          showComma: index < length - 1,
          posInSet: index + 1,
          setSize: length,
        },
        rows,
        options,
        counter,
        ancestors
      );
    });
  } else {
    Array.from(value as Map<unknown, unknown>).forEach(([keyValue, childValue], index) => {
      appendValueRows(
        childValue,
        {
          path: buildMapPath(context.path, keyValue, index),
          level: context.level + 1,
          displayKey: formatKeyDisplay(keyValue),
          keyValue,
          showComma: index < length - 1,
          posInSet: index + 1,
          setSize: length,
        },
        rows,
        options,
        counter,
        ancestors
      );
    });
  }

  rows.push(
    createNode(counter, context, getContainerNodeType(kind, "end"), getContainerContent(kind, "end"), value, {
      length,
      hasToggle: false,
      isExpanded: expanded,
      isLeaf: false,
      key: undefined,
      displayKey: undefined,
      keyValue: undefined,
      index: undefined,
    })
  );
}

export function buildVisibleJsonRows(value: unknown, options: BuildVisibleJsonRowsOptions) {
  const rows: JsonViewNode[] = [];
  const counter: LineCounter = { nextLineNumber: 1 };
  appendValueRows(
    value,
    {
      path: options.rootPath,
      level: 0,
      showComma: false,
      posInSet: 1,
      setSize: 1,
    },
    rows,
    options,
    counter,
    new WeakSet<object>()
  );
  return rows;
}