Allow to specify or exclude insert columns

.eslintignore

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+out
 dist
 node_modules
 webpack

CHANGELOG.md

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+## 0.2.8 (Common, Node.js, Web)
+
+### New features
+
+- (Web only) Allow to modify Keep-Alive setting (previously always disabled).
+  Keep-Alive setting **is now enabled by default** for the Web version.
+
+```ts
+import { createClient } from '@clickhouse/client-web'
+const client = createClient({ keep_alive: { enabled: true } })
+```
+
+- (Node.js & Web) It is now possible to either specify a list of columns to insert the data into or a list of excluded columns:
+
+```ts
+// Generated query: INSERT INTO mytable (message) FORMAT JSONEachRow
+await client.insert({
+  table: 'mytable',
+  format: 'JSONEachRow',
+  values: [{ message: 'foo' }],
+  columns: ['message'],
+})
+
+// Generated query: INSERT INTO mytable (* EXCEPT (message)) FORMAT JSONEachRow
+await client.insert({
+  table: 'mytable',
+  format: 'JSONEachRow',
+  values: [{ id: 42 }],
+  columns: { except: ['message'] },
+})
+```
+
+See also the new examples:
+
+- [Including specific columns or excluding certain ones instead](./examples/insert_exclude_columns.ts)
+- [Leveraging this feature](./examples/insert_ephemeral_columns.ts) when working with
+  [ephemeral columns](https://clickhouse.com/docs/en/sql-reference/statements/create/table#ephemeral)
+  ([#217](https://github.com/ClickHouse/clickhouse-js/issues/217))
+
 ## 0.2.7 (Common, Node.js, Web)
 
 ### New features

examples/insert_ephemeral_columns.ts

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+import { createClient } from '@clickhouse/client' // or '@clickhouse/client-web'
+
+// Ephemeral columns documentation: https://clickhouse.com/docs/en/sql-reference/statements/create/table#ephemeral
+// This example is inspired by https://github.com/ClickHouse/clickhouse-js/issues/217
+void (async () => {
+  const tableName = 'insert_ephemeral_columns'
+  const client = createClient({
+    clickhouse_settings: {
+      allow_experimental_object_type: 1, // allows JSON type usage
+    },
+  })
+
+  await client.command({
+    query: `
+      CREATE OR REPLACE TABLE ${tableName}
+      (
+        event_type  LowCardinality(String) DEFAULT JSONExtractString(message_raw, 'type'),
+        repo_name   LowCardinality(String) DEFAULT JSONExtractString(message_raw, 'repo', 'name'),
+        message     JSON                   DEFAULT message_raw,
+        message_raw String                 EPHEMERAL
+      )
+      ENGINE MergeTree()
+      ORDER BY (event_type, repo_name)
+    `,
+  })
+
+  await client.insert({
+    table: tableName,
+    values: [
+      {
+        message_raw: {
+          type: 'MyEventType',
+          repo: {
+            name: 'foo',
+          },
+        },
+      },
+      {
+        message_raw: {
+          type: 'SomeOtherType',
+          repo: {
+            name: 'bar',
+          },
+        },
+      },
+    ],
+    format: 'JSONEachRow',
+    // The name of the ephemeral column has to be specified here
+    // to trigger the default values logic for the rest of the columns
+    columns: ['message_raw'],
+  })
+
+  const rows = await client.query({
+    query: `SELECT * FROM ${tableName}`,
+    format: 'JSONCompactEachRowWithNames',
+  })
+
+  console.info(await rows.text())
+  await client.close()
+})()

examples/insert_exclude_columns.ts

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+import { createClient } from '@clickhouse/client' // or '@clickhouse/client-web'
+
+void (async () => {
+  const tableName = 'insert_exclude_columns'
+  const client = createClient()
+
+  await client.command({
+    query: `
+      CREATE OR REPLACE TABLE ${tableName}
+      (id UInt32, message String)
+      ENGINE MergeTree()
+      ORDER BY (id)
+    `,
+  })
+
+  /**
+   * Explicitly specifying a list of columns to insert the data into
+   */
+  await client.insert({
+    table: tableName,
+    values: [{ message: 'foo' }],
+    format: 'JSONEachRow',
+    // `id` column value for this row will be zero
+    columns: ['message'],
+  })
+
+  await client.insert({
+    table: tableName,
+    values: [{ id: 42 }],
+    format: 'JSONEachRow',
+    // `message` column value for this row will be an empty string
+    columns: ['id'],
+  })
+
+  /**
+   * Alternatively, it is possible to exclude certain columns instead
+   */
+  await client.insert({
+    table: tableName,
+    values: [{ message: 'bar' }],
+    format: 'JSONEachRow',
+    // `id` column value for this row will be zero
+    columns: {
+      except: ['id'],
+    },
+  })
+
+  await client.insert({
+    table: tableName,
+    values: [{ id: 144 }],
+    format: 'JSONEachRow',
+    // `message` column value for this row will be an empty string
+    columns: {
+      except: ['message'],
+    },
+  })
+
+  const rows = await client.query({
+    query: `SELECT * FROM ${tableName} ORDER BY id, message DESC`,
+    format: 'JSONEachRow',
+  })
+
+  console.info(await rows.json())
+  await client.close()
+})()