perspective data pattern

packages/datalib/src/PerspectiveDataPattern.ts

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+import { PerspectiveDataLoader } from './PerspectiveDataLoader';
+import { PerspectiveDataLoadProps } from './PerspectiveDataProvider';
+import _isString from 'lodash/isString';
+import _isPlainObject from 'lodash/isPlainObject';
+import _isNumber from 'lodash/isNumber';
+import _isBoolean from 'lodash/isBoolean';
+
+export type PerspectiveDataPatternColumnType = 'null' | 'string' | 'number' | 'boolean' | 'object';
+
+export interface PerspectiveDataPatternColumn {
+  name: string;
+  types: PerspectiveDataPatternColumnType[];
+  columns: PerspectiveDataPatternColumn[];
+}
+
+export interface PerspectiveDataPattern {
+  conid: string;
+  database: string;
+  schemaName: string;
+  pureName: string;
+  columns: PerspectiveDataPatternColumn[];
+}
+
+export type PerspectiveDataPatternDict = { [designerId: string]: PerspectiveDataPattern };
+
+function detectValueType(value): PerspectiveDataPatternColumnType {
+  if (_isString(value)) return 'string';
+  if (_isNumber(value)) return 'number';
+  if (_isBoolean(value)) return 'boolean';
+  if (value == null) return 'null';
+}
+
+function addObjectToColumns(columns: PerspectiveDataPatternColumn[], row) {
+  if (_isPlainObject(row)) {
+    for (const key of Object.keys(row)) {
+      let column: PerspectiveDataPatternColumn = columns.find(x => x.name == key);
+      if (!column) {
+        column = {
+          name: key,
+          types: [],
+          columns: [],
+        };
+        columns.push(column);
+      }
+      const type = detectValueType(row[key]);
+      if (!column.types.includes(type)) {
+        column.types.push(type);
+      }
+    }
+  }
+}
+
+export function analyseDataPattern(
+  patternBase: Omit<PerspectiveDataPattern, 'columns'>,
+  rows: any[]
+): PerspectiveDataPattern {
+  const res: PerspectiveDataPattern = {
+    ...patternBase,
+    columns: [],
+  };
+  for (const row of rows) {
+    addObjectToColumns(res.columns, row);
+  }
+  return res;
+}