Advanced

Schema class is essentially for DynamoQL internal usage, however it exposes some usefull properties and methods in case you look for them.

for our examples we are using this Schema defintion.

DynamoQL

import { Schema } from "dynamoql";

const messageSchema = new Schema({
  conversationId: {
    type: Number,
    primaryIndex: true,
  },
  messageId: {
    type: Date,
    format: "timestamp",
    sortKey: true
  },
  text: String,
  author: {
    type: Object,
    fields: {
        id: String,
        nickname: String,
        socialNetwork: {
            type: Array,
            items: {
                type: Object,
                fields: {
                    url: String,
                    label: {
                        type: String,
                        required: true,
                        enum: ["X", "Facebook", "Instagram"]
                    }
                }
            }
        }
    }
  },
  response: {
    type: Set,
    items: String
  }
} as const);

produced type

interface ISocialNetwork {
    url: string;
    label: "X" | "Facebook" | "Instagram"
}


interface IMessage {
    conversationId: number;
    messageId: number;
    text: string;
    author: {
        id: string:
        nickname: string;
        socialNetwork: ISocialNetwork[]
    },
    response?: Set<string>
}

marshallPk

This method is specially usefull when working with indices with Date type.

Schema.prototype.marshallPk takes one argument:

• of type String, Number or Buffer, Date, depending on your primaryIndex, in our example its a Number.

const marshalledPk = messageSchema.marshallPk(237190);

// returns
marshalledPk = {
    conversationId: {
        N: 237190
    }
}

• or a JS object which includes your primaryIndex and optionnally sortKey.

const marshalledPk = messageSchema.marshallPk({
     conversationId: 237190,
     messageId: "2023-12-18T13:12:34.797Z"
     });

// returns
marshalledPk = {
    conversationId: {
        N: 237190
    },
    messageId: {
        N: 1702905154797
    }
}

getTypeFromKeyPath

This method allows you to find type declaration object with a key-path.

const fieldType = messageSchema.getTypeFromKeyPath("conversationId");

// returns
fieldType = {
    type: "N",
    primaryIndex: true,
    required: true
}

const fieldType = messageSchema.getTypeFromKeyPath("author.socialNetwork[2].label");

// returns
fieldType = {
    type: "S",
    required: true,
    enum: ["X", "Facebook", "Instagram"]
}