feat: added model to represent and construct filters when querying for records

src/models/QueryFilter.ts

@@ -0,0 +1,43 @@
+import { FilterOperators } from '../enums/FilterOperators';
+
+export class QueryFilter {
+  public fieldId: number;
+  public operator: FilterOperators;
+  public value: string | number | Date | null;
+
+  constructor(
+    fieldId: number,
+    operator: FilterOperators,
+    value: string | number | Date | null
+  ) {
+    if (
+      value === null &&
+      operator !== FilterOperators.IsNull &&
+      operator !== FilterOperators.NotNull
+    ) {
+      throw new Error('Value cannot be null for this operator');
+    }
+
+    this.fieldId = fieldId;
+    this.operator = operator;
+    this.value = value;
+  }
+
+  public toString(): string {
+    if (this.value == null) {
+      return `${this.fieldId} ${this.operator}`;
+    }
+
+    if (this.value instanceof Date) {
+      return `${this.fieldId} ${
+        this.operator
+      } datetime'${this.value.toISOString()}'`;
+    }
+
+    if (typeof this.value === 'string') {
+      return `${this.fieldId} ${this.operator} '${this.value}'`;
+    }
+
+    return `${this.fieldId} ${this.operator} ${this.value}`;
+  }
+}