feat: infer sheet context based on provided schema & selected columns

Author: ChronicStone

example.xlsx

@@ -3,7 +3,7 @@ import xlsx, { type IColumn, type IJsonSheet, getWorksheetColumnWidths } from 'j
 import type { CellStyle } from 'xlsx-js-style'
 import XLSX from 'xlsx-js-style'
 import { deepmerge } from 'deepmerge-ts'
-import type { CellValue, Column, ColumnGroup, ExcelSchema, GenericObject, NestedPaths, Not, Sheet, TransformersMap, ValueTransformer } from './types'
+import type { CellValue, Column, ColumnGroup, ExcelSchema, GenericObject, NestedPaths, Not, SchemaColumnKeys, Sheet, TransformersMap, ValueTransformer } from './types'
 import { formatKey, getPropertyFromPath, getSheetCellKey } from './utils'
 
 export class ExcelSchemaBuilder<
@@ -85,7 +85,7 @@ export class ExcelSchemaBuilder<
 }
 
 export class ExcelBuilder<UsedSheetKeys extends string = never> {
-  private sheets: Array<Sheet<any, ExcelSchema<any, any, any>>> = []
+  private sheets: Array<Sheet<any, ExcelSchema<any, any, any>, any, any>> = []
 
   public static create(): ExcelBuilder {
     return new ExcelBuilder()
@@ -95,9 +95,11 @@ export class ExcelBuilder<UsedSheetKeys extends string = never> {
     Key extends string,
     T extends GenericObject,
     Schema extends ExcelSchema<T, any, string>,
+    ColKeys extends SchemaColumnKeys<Schema>,
+    SelectCols extends { [key in ColKeys]?: boolean } = {},
   >(
     key: Not<Key, UsedSheetKeys>,
-    sheet: Omit<Sheet<T, Schema>, 'sheetKey'>,
+    sheet: Omit<Sheet<T, Schema, ColKeys, SelectCols>, 'sheetKey'>,
   ): ExcelBuilder<UsedSheetKeys | Key> {
     if (this.sheets.some(s => s.sheetKey === key))
       throw new Error(`Sheet with key '${key}' already exists.`)

src/index.ts

@@ -27,6 +27,10 @@ export type TypeFromPath<T extends GenericObject, Path extends string> =
         : never
       : never
 
+export type AllKeysMatch<T extends object, U> = {
+  [K in keyof T]: T[K] extends U ? true : false;
+}[keyof T] extends true ? true : false
+
 export type CellValue = string | number | boolean | null | undefined | Date
 
 export type ValueTransformer = (value: any) => CellValue
@@ -109,12 +113,36 @@ export type SchemaColumnKeys<
 export type Sheet<
   T extends GenericObject,
   Schema extends ExcelSchema<T, any, string, any>,
+  ColumnKeys extends SchemaColumnKeys<Schema>,
+  SelectColsMap extends { [key in ColumnKeys]?: boolean } | never,
+  SelectedCols extends string = ExtractSelectedColumns<ColumnKeys, SelectColsMap>,
+  ContextMap extends { [key: string]: any } = ExtractContextMap<Schema>,
+  SelectedContextMap extends ExtractSelectedContext<ContextMap, SelectedCols> = ExtractSelectedContext<ContextMap, SelectedCols>,
 > = {
   sheetKey: string
   schema: Schema
   data: T[]
-  select?: { [K in SchemaColumnKeys<Schema>]?: boolean }
+  select?: SelectColsMap
   context?: {}
-} & (Schema extends ExcelSchema<T, any, any, infer Ctx>
-  ? keyof Ctx extends never ? {} : { context: Ctx }
-  : {})
+} & (keyof SelectedContextMap extends never ? {} : { context: SelectedContextMap })
+
+export type ExtractContextMap<
+  Schema extends ExcelSchema<any, any, string, any>,
+> = Schema extends ExcelSchema<any, any, any, infer Ctx> ? Ctx : {}
+
+export type ExtractSelectedColumns<
+  ColKeys extends string,
+  SelectCols extends { [key in ColKeys]?: boolean },
+> = keyof SelectCols extends never ? ColKeys :
+  AllKeysMatch<SelectCols, false> extends true
+    ? Exclude<ColKeys, keyof SelectCols>
+    : {
+        [K in ColKeys]: SelectCols[K] extends true ? K : never;
+      }[ColKeys]
+
+export type ExtractSelectedContext<
+  ContextMap extends { [key: string]: any },
+  SelectedCols extends string,
+> = {
+  [K in keyof ContextMap as K extends SelectedCols ? K : never]: ContextMap[K];
+}

src/types.ts

@@ -99,23 +99,25 @@ describe('should', () => {
       .sheet('sheet1', {
         data: users,
         schema: assessmentExport,
+        select: {
+          'group:org': true,
+        },
         context: {
           'group:org': organizations,
-
         },
+
       })
       .sheet('sheet2', {
         data: users,
         schema: assessmentExport,
         select: {
-          firstName: true,
-          lastName: true,
-          email: true,
-          // 'group:org': true,
+          'firstName': true,
+          'lastName': false,
+          'email': false,
+          'group:org': false,
         },
         context: {
-          'group:org': organizations,
-
+          // 'group:org': organizations,
         },
       })
       .sheet('sheet3', {