type-dynamodb is simple but powerful dynamodb ORM that uses decorators to get the most benefits from typescript and OOP like inheritance, override methods and adding multiple layers of decorators.
- first install the lib and its peerDependencies
npm i class-transformer aws-sdk type-dynamodb --save- install reflect-metadata :
npm install `reflect-metadata` --save
- add
reflect-metadatato the root file of your project
import "reflect-metadata";- make sure to set AWS credients in your env variables using command line or .env ...etc:
export AWS_ACCESS_KEY_ID=<AWS_ID> # macos or linux
export AWS_SECRET_ACCESS_KEY=<AWS_ACCESS_KEY>
export AWS_DEFAULT_REGION=<AWS_REGION>or here for other os.
- in typescript, you need to add the following config to your
tsconfig.json:
"emitDecoratorMetadata": true,
"experimentalDecorators": true,1- first we add @DyTable decorator and extends BaseDyTable to get the db functionalities.
@DyTable('<TableName>') // default is User
class User extends BaseDyTable{
id: string
name: string
userPassword: string
created: string
}2- then we determined which fields are part of our dynamodb table by adding @DyField:
@DyTable()
class User extends BaseDyTable{
@DyField()
id: string
@DyField()
name: string
@DyField()
userPassword: string
@DyField()
created: string
}3- then we specify the partition key field in @DyField and sorting key fields if exist:
...
@DyField({isPartitionKey: true})
id: string
@DyField({isSortingKey: true})
created: string
...4- now we can use the db functions (dyGet, dyUpdate, dyDelete, dyPut, dyScan, dyQuery) as shown here:
/* using await */
const user = await User.dyGet({id: "id1"})
await user.dyUpdate({userPassword: "12345"});
await user.dyDelete();
// scan function
const scannedUsers = await User.dyScan(
{
filter: {
created: {range: {to:"<ISOSTRING>"}},
name: {equal: "Amro"}
},// note every key can have only one filter parameter.
limit: 50,
}
);
// faster query method that uses PartitionKey(must be specified) and specify sortingKey automatically
const users = await User.dyQuery(
"PARTITION_KEY_VALUE",
{
filter: {
created: {range: {from:"<ISOSTRING>"}},
name: {contains: "Amro"}
}
}
);
/* using then */
User.dyGet({id: "user1"})
.then((user)=> user.dyUpdate( {userPassword: "12345"}))
.then((updatedUser)=> {
// some other logic
updatedUser.dyDelete();
})- for specifying local and global secondary index, use the following decorators:
@DyTable()
class User {
...
@DyGlobalSecondaryIndex("name_index", {isPartitionKey: true})
@DyField()
name: string
@DyLocalSecondaryIndex("created_index")
@DyField({isSortingKey: true})
created: string
...
}- to use it specify the IndexName in the filter options:
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