null check fixed

Author: ackava

src/query/ast/ExpressionToSql.ts

@@ -493,21 +493,43 @@ export default class ExpressionToSql extends Visitor<ITextQuery> {
                 }
             }
 
+            const [r1] = right;
             switch(operator) {
-                case "!==":
-                case "!=":
-                    return prepare `${left} <> ${right}`;
                 case "===":
                 case "==":
+                case "=":
+                    if (right.length === 1 && typeof r1 === "function") {
+                        const t = (p) => r1(p) === null
+                            ? [ ... left, " IS NULL"]
+                            : [ ... left, " = ", ... right.flatMap((x) => typeof x === "function" ? () => x(p) : x)];
+                        return [t];
+                    }
                     return prepare `${left} = ${right}`;
+                case "<>":
+                case "!==":
+                case "!=":
+                    if (right.length === 1 && typeof r1 === "function") {
+                        const t = (p) => r1(p) === null
+                            ? [ ... left, " IS NOT NULL"]
+                            : [ ... left, " <> ", ... right.flatMap((x) => typeof x === "function" ? () => x(p) : x)];
+                        return [t];
+                    }
+                    return prepare `${left} <> ${right}`;
             }
 
         } else {
             switch(operator) {
                 case "!==":
                 case "!=":
-                    operator = "<>";
-                    break;
+                case "<>":
+                    const [r1] = right;
+                    if (right.length === 1 && typeof r1 === "function") {
+                        const t = (p) => r1(p) === null
+                            ? [ ... left, " IS NOT NULL"]
+                            : [ ... left, " <> ", ... right.flatMap((x) => typeof x === "function" ? () => x(p) : x)];
+                        return [t];
+                    }
+                    return prepare `${left} <> ${right}`;
                 case "===":
                 case "==":
                     operator = "=";

src/tests/expressions/simple/parse-null.ts

@@ -0,0 +1,33 @@
+import assert from "assert";
+import Sql from "../../../sql/Sql.js";
+import QueryCompiler from "../../../compiler/QueryCompiler.js";
+
+export default function () {
+
+    const compiler = QueryCompiler.instance;
+
+    let name = "1";
+
+    let r = compiler.execute({ name }, (p) => (x) => x.firstName === p.name);
+    assert.equal(`x."firstName" = $1`, r.text);
+
+    name = null;
+    r = compiler.execute({ name }, (p) => (x) => x.firstName === p.name);
+    assert.equal(`x."firstName" IS NULL`, r.text);
+
+    r = compiler.execute({ name }, (p) => (x) => x.firstName === null);
+    assert.equal(`x."firstName" IS NULL`, r.text);
+
+    name = "1";
+
+    r = compiler.execute({ name }, (p) => (x) => x.firstName !== p.name);
+    assert.equal(`x."firstName" <> $1`, r.text);
+
+    name = null;
+    r = compiler.execute({ name }, (p) => (x) => x.firstName !== p.name);
+    assert.equal(`x."firstName" IS NOT NULL`, r.text);
+
+    r = compiler.execute({ name }, (p) => (x) => x.firstName !== null);
+    assert.equal(`x."firstName" IS NOT NULL`, r.text);
+}
+