JavaScript API

import { DDB } from 'dolphindb'
// The import method for existing projects using CommonJS modules is const { DDB } = await import('dolphindb')
// Use in browser: import { DDB } from 'dolphindb/browser.js'

// Initially connect to an instance of DolphinDB using the WebSocket URL (without establishing an actual network connection)
let ddb = new DDB('ws://127.0.0.1:8848')

// Encrypt with HTTPS
// let ddb = new DDB('wss://dolphindb.com')

// Establish a connection to DolphinDB (requires DolphinDB database version at least 1.30.16 or 2.00.4)
await ddb.connect()

<script type="module">
    import { DDB } from 'https://cdn.dolphindb.cn/assets/api.js'
    
    let ddb = new DDB('ws://127.0.0.1:8848')
    
    await ddb.connect()
</script>

Code completion, function prompt data:https://cdn.dolphindb.cn/assets/docs.zh.jsonhttps://cdn.dolphindb.cn/assets/docs.en.json

let ddb = new DDB('ws://127.0.0.1:8848')

// Encrypt with HTTPS
let ddbsecure = new DDB('wss://dolphindb.com', {
    // Whether to log in automatically after establishing a connection, default `true`
    autologin: true,
    
    // DolphinDB username, default `'admin'`
    username: 'admin',
    
    // DolphinDB password, default `'123456'`
    password: '123456',
    
    // set python session flag, default `false`
    python: false,
    
    // set sql standrd flag,  use the SqlStandard enum to pass arguments, default `DolphinDB`
    // sql: SqlStandard.MySQL,
    // sql: SqlStandard.Oracle,
    
    // After setting this option, the database connection is only used for streaming data. For details, see `5. Streaming Data`
    streaming: undefined
})

import { DdbInt } from 'dolphindb'

const result = await ddb.call('add', [new DdbInt(1), new DdbInt(1)])
// TypeScript: const result = await ddb.call<DdbInt>('add', [new DdbInt(1), new DdbInt(1)])

console.log(result.value === 2)  // true

In the above example, two parameters 1 (corresponding to the int type in DolphinDB) are uploaded to the DolphinDB database as parameters of the add function, then the result of the function call is received.

<DdbInt> is used by TypeScript to infer the type of the return value

• result is a DdbInt, which is also a DdbObj<number>

• result.form is a DdbForm.scalar

• result.type is a DdbType.int

• result.value is native number in JavaScript (the value range and precision of int can be accurately represented by JavaScript number)

It is recommended to first understand the concepts related to TypedArray in JavaScript, you can refer to:https://stackoverflow.com/questions/42416783/where-to-use-arraybuffer-vs-typed-array-in-javascripthttps://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray

/** Can represent all data types in DolphinDB databases */
class DdbObj <T extends DdbValue = DdbValue> {
    /** is it little endian */
    le: boolean
    
    /** data form https://www.dolphindb.cn/cn/help/DataTypesandStructures/DataForms/index.html */
    form: DdbForm
    
    /** data type  https://www.dolphindb.cn/cn/help/DataTypesandStructures/DataTypes/index.html */
    type: DdbType
    
    /** consumed length in buf parsed */
    length: number
    
    /** table name / column name */
    name?: string
    
    /**
        Lowest dimension
        - vector: rows = n, cols = 1
        - pair:   rows = 2, cols = 1
        - matrix: rows = n, cols = m
        - set:    the same as vector
        - dict:   include keys, values vector
        - table:  the same as matrix
    */
    rows?: number
    
    /** 2nd dimension */
    cols?: number
    
    /** the actual data. Different DdbForm, DdbType use different types in DdbValue to represent actual data */
    value: T
    
    /** raw binary data, only top-level objects generated by parse_message when parse_object is false have this attribute */
    buffer?: Uint8Array
    
    constructor (data: Partial<DdbObj> & { form: DdbForm, type: DdbType, length: number }) {
        Object.assign(this, data)
    }
}

class DdbInt extends DdbObj<number> {
    constructor (value: number) {
        super({
            form: DdbForm.scalar,
            type: DdbType.int,
            length: 4,
            value
        })
    }
}

// ... There are also many utility classes, such as DdbString, DdbLong, DdbDouble, DdbVectorDouble, DdbVectorAny, etc.

type DdbValue = 
    null | boolean | number | \[number, number\] | bigint | string | string\[\] | 
    Uint8Array | Int16Array | Int32Array | Float32Array | Float64Array | BigInt64Array | Uint8Array\[\] | 
    DdbObj\[\] | DdbFunctionDefValue | DdbSymbolExtendedValue
    

enum DdbForm {
    scalar = 0,
    vector = 1,
    pair = 2,
    matrix = 3,
    set = 4,
    dict = 5,
    table = 6,
    chart = 7,
    chunk = 8,
}


enum DdbType {
    void = 0,
    bool = 1,
    char = 2,
    short = 3,
    int = 4,
    long = 5,
    // ...
    timestamp = 12,
    // ...
    double = 16,
    symbol = 17,
    string = 18,
    // ...
}

async call <T extends DdbObj> (
    /** function name */
    func: string,
    
    /** function arguments (The incoming native string and boolean will be automatically converted to DdbObj<string> and DdbObj<boolean>) */
    args?: (DdbObj | string | boolean)[] = [ ],
    
    /** calling options */
    options?: {
        /** Urgent flag. Use urgent worker to execute to prevent being blocked by other jobs */
        urgent?: boolean
        
        /** When the node alias is set, the function is sent to the corresponding node in the cluster for execution (using the rpc method in DolphinDB) */
        node?: string
        
        /** When setting multiple node aliases, send them to the corresponding multiple nodes in the cluster for execution (using the pnodeRun method in DolphinDB) */
        nodes?: string[]
        
        /** It must be passed when setting the node parameter, the function type needs to be specified, and it is not passed in other cases */
        func_type?: DdbFunctionType
        
        /** It may be  passed when setting the nodes parameter, otherwise may not be passed */
        add_node_alias?: boolean
    } = { }
): Promise<T>

const result = await ddb.eval(
    'def foo (a, b) {\n' +
    '    return a + b\n' +
    '}\n' +
    'foo(1l, 1l)\n'
)

// TypeScript:
// import type { DdbLong } from 'dolphindb'
// const result = await ddb.eval<DdbLong>(...)

console.log(result.value === 2n)  // true

In the above example, a script is uploaded through a string to the DolphinDB database for execution, and the execution result of the last statement foo(1l, 1l) is received.

<DdbLong> is used by TypeScript to infer the type of the return value

• result is a DdbLong, which is also a DdbObj<bigint>

• result.form is DdbForm.scalar

• result.type is DdbType.long

• result.value is the native bigint in JavaScript (the precision of long cannot be accurately represented by JavaScript number, but it can be represented by bigint)

As long as the WebSocket connection is not disconnected, the custom function foo will always exist in the subsequent session and can be reused, for example, you can use await ddb.call<DdbInt>('foo', [new DdbInt(1), new DdbInt(1)]) to call this custom function

async eval <T extends DdbObj> (
    /** the script to execute */
    script: string,
    
    /** calling options */
    options: {
        /** Urgent flag. Use urgent worker to execute to prevent being blocked by other jobs */
        urgent?: boolean
    } = { }
): Promise<T>

import { DdbVectorDouble } from 'dolphindb'

let a = new Array(10000)
a.fill(1.0)

ddb.upload(['bar1', 'bar2'], [new DdbVectorDouble(a), new DdbVectorDouble(a)])

In the above example, two variables bar1, bar2 are uploaded, and the variable value is a double vector of length 10000

As long as the WebSocket connection is not disconnected, the variables bar1, bar2 will always exist in the subsequent session and can be reused

async upload (
    /** variable names */
    vars: string[],
    
    /** variable values */
    args: (DdbObj | string | boolean)[]
): Promise<void>