feat: generate separate insert types (#3)

* feat: add support for generating separate insert types

* docs: update readme

* fix: skip insert types for views

* docs: update readme

* docs: update readme

* docs: update readme

* refactor: option description

* test: fix tests

* test: fix connection string init

* test: add tests for generating insert types

* fix: add missing ts types

README.md

@@ -46,6 +46,7 @@ Options:
   --pascal-enums             transform enum keys to pascal case (default: false)
   --bigint                   use bigint for int8 types instead of strings (default: false)
   --date-as-string           use string for date types instead of javascript Date object (default: false)
+  --insert-types             generate separate insert types with optional fields for columns allowing NULL value or having default values (default: false)
   --help                     display help for command
 
 Example:
@@ -85,6 +86,52 @@ interface UserEntity {
 
 > By default, the types will be generated based on how [pg](https://github.com/brianc/node-postgres) returns the values.
 
+#### Insert types
+To simplify database inserts, separate types can be generated with optional values where NULL is allowed or default values for column exist in postgres.
+
+Given database table
+```sql
+CREATE TYPE user_state AS ENUM (
+  'asleep',
+  'awake'
+);
+
+CREATE TABLE users (
+    id int4 NOT NULL,
+    name varchar(255) NOT NULL,
+    state user_state,
+    is_enabled bool NOT NULL DEFAULT FALSE
+);
+```
+
+Running `pg-typegen -o ./entities.ts --insert-types postgres://username:password@localhost:5432/database`
+Will generate the following type definitions
+```ts
+enum UserState {
+  asleep = 'asleep',
+  awake = 'awake'
+}
+
+interface UserEntity {
+  id: number;
+  name: string;
+  state: UserState | null;
+  is_enabled: boolean;
+}
+
+interface UserInsertEntity {
+  id?: number;
+  name: string;
+  state?: UserState | null;
+  is_enabled?: boolean;
+}
+```
+
+Which should allow simplified inserts when coupled with libraries like [knex](https://github.com/knex/knex)
+```ts
+knex<UserInsertEntity>('users').insert({ name: 'foo' })
+```
+
 ### Running from code
 
 ```ts

index.d.ts

@@ -12,6 +12,7 @@ export interface Options {
   bigint?: boolean;
   dateAsString?: boolean;
   ssl?: boolean;
+  insertTypes?: boolean;
 }
 
 declare function generate(option: Options): Promise<string>;

index.js

@@ -25,6 +25,7 @@ program
   .option('--pascal-enums', 'transform enum keys to pascal case', false)
   .option('--bigint', 'use bigint for int8 types instead of strings', false)
   .option('--date-as-string', 'use string for date types instead of javascript Date object', false)
+  .option('--insert-types', 'generate separate insert types with optional fields for columns allowing NULL value or having default values', false)
 
 program.on('--help', () => {
   console.log('')

lib/postgres.js

@@ -19,16 +19,19 @@ const typeMapping = {
 
 function getTableDefinitions (sql, schema) {
   return sql`
-    SELECT table_name AS name,
+    SELECT c.table_name AS name,
+           t.table_type = 'VIEW' AS "isView",
            jsonb_agg(
                    DISTINCT jsonb_build_object(
                    'name', column_name,
                    'type', udt_name,
+                   'hasDefault', column_default IS NOT NULL OR (is_identity = 'YES' AND identity_generation = 'ALWAYS'),
                    'isNullable', is_nullable::boolean
                )) AS columns
-    FROM information_schema.columns
-    WHERE table_schema = ${schema}
-    GROUP BY table_name
+    FROM information_schema.columns c
+    INNER JOIN information_schema.tables t ON t.table_name = c.table_name 
+    WHERE c.table_schema = ${schema}
+    GROUP BY c.table_name, t.table_type
   `
 }
 
@@ -40,6 +43,7 @@ async function getMaterializedViewDefinitions (sql, schema) {
         WHERE schemaname = ${schema}
     )
     SELECT pc.relname AS name,
+           true AS "isView",
            jsonb_agg(
                    DISTINCT jsonb_build_object(
                    'name', pa.attname,

lib/typescript.js

@@ -62,9 +62,7 @@ function getColumnType (typeMapping, type, enums) {
   return result[0]
 }
 
-function getTableType (opts, tableName) {
-  const { suffix } = opts
-
+function getTableType (opts, tableName, suffix) {
   let parsedTableName = toPascalCase(tableName)
   if (parsedTableName.endsWith('ies')) {
     parsedTableName = parsedTableName.slice(0, -3) + 'y'
@@ -86,7 +84,7 @@ function generateTableTypes (opts, tables, typeMapping, enums) {
     .filter(table => !opts.exclude.includes(table.name))
     .sort(sortByField('name'))
     .map(table => {
-      let tableType = getTableType(opts, table.name)
+      let tableType = getTableType(opts, table.name, opts.suffix)
 
       if (table.columns.length > 0) {
         tableType += '\n'
@@ -99,6 +97,24 @@ function generateTableTypes (opts, tables, typeMapping, enums) {
         })
 
       tableType += `}${semicolon(opts)}\n`
+
+      if (opts.insertTypes && !table.isView) {
+        tableType += '\n'
+        tableType += getTableType(opts, table.name, `Insert${opts.suffix}`)
+
+        if (table.columns.length > 0) {
+          tableType += '\n'
+        }
+
+        table.columns
+          .sort(sortByField('name'))
+          .forEach(tableColumn => {
+            tableType += `  ${formatName(tableColumn.name)}${tableColumn.isNullable || tableColumn.hasDefault ? '?' : ''}: ${getColumnType(typeMapping, tableColumn.type, enums)}${tableColumn.isNullable && !opts.optionals ? ' | null' : ''}${semicolon(opts)}\n`
+          })
+
+        tableType += `}${semicolon(opts)}\n`
+      }
+
       return tableType
     }).join('\n')
 }