Add support for Statement.pluck() (#171)

Author: penberg

index.js

@@ -118,7 +118,7 @@ class Database {
   prepare(sql) {
     try {
       const stmt = databasePrepareSync.call(this.db, sql);
-      return new Statement(stmt);  
+      return new Statement(stmt);
     } catch (err) {
       throw convertError(err);
     }
@@ -282,6 +282,7 @@ class Database {
 class Statement {
   constructor(stmt) {
     this.stmt = stmt;
+    this.pluckMode = false;
   }
 
   /**
@@ -294,6 +295,16 @@ class Statement {
     return this;
   }
 
+  /**
+   * Toggle pluck mode.
+   *
+   * @param pluckMode Enable or disable pluck mode. If you don't pass the parameter, pluck mode is enabled.
+   */
+  pluck(pluckMode) {
+    this.pluckMode = pluckMode ?? true;
+    return this;
+  }
+
   get reader() {
     return statementIsReader.call(this.stmt);
   }
@@ -307,7 +318,7 @@ class Statement {
         return statementRun.call(this.stmt, bindParameters[0]);
       } else {
         return statementRun.call(this.stmt, bindParameters.flat());
-      }  
+      }
     } catch (err) {
       throw convertError(err);
     }
@@ -378,7 +389,11 @@ class Statement {
     try {
       const result = [];
       for (const row of this.iterate(...bindParameters)) {
-        result.push(row);
+        if (this.pluckMode) {
+          result.push(row[Object.keys(row)[0]]);
+        } else {
+          result.push(row);
+        }
       }
       return result;
     } catch (err) {

integration-tests/tests/async.test.js

@@ -149,6 +149,17 @@ test.serial("Statement.all() [raw]", async (t) => {
   t.deepEqual(await stmt.raw().all(), expected);
 });
 
+test.serial("Statement.all() [pluck]", async (t) => {
+  const db = t.context.db;
+
+  const stmt = await db.prepare("SELECT * FROM users");
+  const expected = [
+    1,
+    2,
+  ];
+  t.deepEqual(await stmt.pluck().all(), expected);
+});
+
 test.serial("Statement.all() [default safe integers]", async (t) => {
   const db = t.context.db;
   db.defaultSafeIntegers();
@@ -298,9 +309,9 @@ test.serial("errors", async (t) => {
 test.serial("Database.prepare() after close()", async (t) => {
   const db = t.context.db;
   await db.close();
-  await t.throwsAsync(async () => {    
+  await t.throwsAsync(async () => {
     await db.prepare("SELECT 1");
-  }, { 
+  }, {
     instanceOf: TypeError,
     message: "The database connection is not open"
   });
@@ -309,9 +320,9 @@ test.serial("Database.prepare() after close()", async (t) => {
 test.serial("Database.exec() after close()", async (t) => {
   const db = t.context.db;
   await db.close();
-  await t.throwsAsync(async () => {    
+  await t.throwsAsync(async () => {
     await db.exec("SELECT 1");
-  }, { 
+  }, {
     instanceOf: TypeError,
     message: "The database connection is not open"
   });
@@ -397,4 +408,4 @@ const connect = async (path_opt, options = {}) => {
 /// Generate a unique database filename
 const genDatabaseFilename = () => {
   return `test-${crypto.randomBytes(8).toString('hex')}.db`;
-};
+};

integration-tests/tests/sync.test.js

@@ -169,6 +169,17 @@ test.serial("Statement.all() [raw]", async (t) => {
   t.deepEqual(stmt.raw().all(), expected);
 });
 
+test.serial("Statement.all() [pluck]", async (t) => {
+  const db = t.context.db;
+
+  const stmt = db.prepare("SELECT * FROM users");
+  const expected = [
+    1,
+    2,
+  ];
+  t.deepEqual(stmt.pluck().all(), expected);
+});
+
 test.serial("Statement.all() [default safe integers]", async (t) => {
   const db = t.context.db;
   db.defaultSafeIntegers();
@@ -391,9 +402,9 @@ test.serial("errors", async (t) => {
 test.serial("Database.prepare() after close()", async (t) => {
   const db = t.context.db;
   db.close();
-  t.throws(() => {    
+  t.throws(() => {
     db.prepare("SELECT 1");
-  }, { 
+  }, {
     instanceOf: TypeError,
     message: "The database connection is not open"
   });
@@ -402,9 +413,9 @@ test.serial("Database.prepare() after close()", async (t) => {
 test.serial("Database.exec() after close()", async (t) => {
   const db = t.context.db;
   db.close();
-  t.throws(() => {    
+  t.throws(() => {
     db.exec("SELECT 1");
-  }, { 
+  }, {
     instanceOf: TypeError,
     message: "The database connection is not open"
   });
@@ -452,4 +463,4 @@ const connect = async (path_opt, options = {}) => {
 /// Generate a unique database filename
 const genDatabaseFilename = () => {
   return `test-${crypto.randomBytes(8).toString('hex')}.db`;
-};
+};

promise.js

@@ -282,6 +282,7 @@ class Database {
 class Statement {
   constructor(stmt) {
     this.stmt = stmt;
+    this.pluckMode = false;
   }
 
   /**
@@ -294,6 +295,16 @@ class Statement {
     return this;
   }
 
+  /**
+   * Toggle pluck mode.
+   *
+   * @param pluckMode Enable or disable pluck mode. If you don't pass the parameter, pluck mode is enabled.
+   */
+  pluck(pluckMode) {
+    this.pluckMode = pluckMode ?? true;
+    return this;
+  }
+
   get reader() {
     return statementIsReader.call(this.stmt);
   }
@@ -380,7 +391,11 @@ class Statement {
       const result = [];
       const it = await this.iterate(...bindParameters);
       for (const row of it) {
-        result.push(row);
+        if (this.pluckMode) {
+          result.push(row[Object.keys(row)[0]]);
+        } else {
+          result.push(row);
+        }
       }
       return result;
     } catch (e) {