Prevent bind error with undefined/null parameters (#375)

statement.bind(null) initially did not throw an error (and did not bind any parameter either), by chance, because of the way iteration on bind parameters was implemented.

Libraries such as https://github.com/typeorm/typeorm came to depend on this undocumented behavior.

After the port from coffescript to javascript, calling statement.bind with null started to throw an error, which broke some dependent code.

This commit reintroduces the original behavior, documents it, and adds a test for it.

src/api.js

@@ -208,9 +208,11 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
     }
 
     /** @typedef {string|number|null|Uint8Array} Database.SqlValue */
-    /** @typedef {Database.SqlValue[]|Object<string, Database.SqlValue>} Statement.BindParams */
+    /** @typedef {Database.SqlValue[]|Object<string, Database.SqlValue>|null} Statement.BindParams
+     */
 
-    /** Bind values to the parameters, after having reseted the statement
+    /** Bind values to the parameters, after having reseted the statement.
+    * If values is null, do nothing and return true.
     *
     * SQL statements can have parameters, named *'?', '?NNN', ':VVV', '@VVV', '$VVV'*,
     * where NNN is a number and VVV a string.
@@ -251,10 +253,9 @@ Module["onRuntimeInitialized"] = function onRuntimeInitialized() {
             throw "Statement closed";
         }
         this["reset"]();
-        if (Array.isArray(values)) {
-            return this.bindFromArray(values);
-        }
-        return this.bindFromObject(values);
+        if (Array.isArray(values)) return this.bindFromArray(values);
+        if (values != null && typeof values === "object") return this.bindFromObject(values);
+        return true;
     };
 
     /** Execute the statement, fetching the the next line of result,

test/test_statement.js

@@ -65,6 +65,14 @@ exports.test = function(sql, assert){
     result = stmt.get({':start':1, ':end':1});
     assert.deepEqual(result, ['a',1], "Binding named parameters");
 
+    // Prepare statement, pass null to bind() and check that it works
+    stmt = db.prepare("SELECT 'bind-with-null'");
+    result = stmt.bind(null);
+    assert.equal(result, true);
+    stmt.step();
+    result = stmt.get();
+    assert.equal(result,"bind-with-null")
+
     // Close the database and all associated statements
     db.close();
 };