1  export interface FieldMetadata {
 2    /**
 3     * If the field is required but somehow the value we retrieve is `null`,
 4     * we use this default value, if provided.
 5     */
 6    defaultValue?: (() => any) | any;
 7    deserializer?: (value: any, self: InstanceType<any>) => any;
 8    enum?: any;
 9    key: string;
10    /**
11     * All fields are required by default, using `@optional` will
12     * make the field optional by deserializers and serializers.
13     */
14    optional?: boolean;
15    rename?: string;
16  }
17  
18  export function getModelMetadata(clazz: any): Array<FieldMetadata> {
19    return clazz.constructor._propertyMetadata || [];
20  }
21  
22  export function getModelMetadataField(clazz: any, field: string): FieldMetadata | undefined {
23    return getModelMetadata(clazz).find(
24      (local: FieldMetadata) => local.key === field
25    );
26  }
27  
28  export function mutateModelMetadataField(clazz: any, field: string, mutation: (metadata: FieldMetadata) => void): void {
29    if (!clazz.constructor._propertyMetadata) {
30      clazz.constructor._propertyMetadata = [];
31    }
32  
33    const metadata = getModelMetadataField(clazz, field);
34  
35    if (!metadata) {
36      // Will update the locally created reference.
37      const metadata = { key: field };
38      mutation(metadata);
39  
40      // Then we'll push it to metadatas.
41      clazz.constructor._propertyMetadata.push(metadata);
42    }
43    // Will update the reference.
44    else mutation(metadata);
45  }