How to create Near AssemblyScript smart contract project.

How to create Near AssemblyScript smart contract project.

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In this article, I’ll walk you through how to setup NEAR smart contracts in AssemblyScript project in few mins. You will find a copy of the project built following these instructions in this github repository, be sure to follow the steps through to see how it all came together.


I assume you have set up your local NEAR smart contract development environment, you can check out this guide if you haven’t done so.

Steps to create your Near Assemblyscript smart contract project

  1. Create a folder for the project, give it a suitable name
  2. Run npx asinit .
  3. In the terminal, add near-sdk-as by running yarn add -D near-sdk-as
  4. Rename the build folder to out . We’re trying to follow the official near practice as much as possible. When we build the project, the output WASM file should be put in this folder.
  5. Remove the contents of the asconfig.json file in the root. The file should contain the following config code.

       "extends": "near-sdk-as/asconfig.json",
       "outDir": "./out"  

    The second line of the above code means that when we build the project, the output WASM file should be put in a folder named out .

  6. Add a new file named as-pect.config.js file in the root folder. The file should contain the following config code

     module.exports = require("near-sdk-as/imports");
  7. Delete the index.js file from the root folder.

  8. Delete the tests folder. Our tests will be saved in another location.
  9. Run the following set of commands:

     cd assembly && touch as_types.d.ts && mkdir __tests__  && cd __tests__ && touch as-pect.d.ts main.unit.spec.ts

    The assembly folder would contain our smart contract code, tests and some configuration files. The command did the following:

    • it added the assembly-script type definition file as_types.d.ts wherein we would add references to include near-sdk-as types
    • it created a __tests__ folder for our As-spect tests and adds test file main.unit.spec.ts and type definition file as-pect.d.ts.
  10. In assembly/as_types.d.ts add this

    /// <reference types="near-sdk-as/assembly/as_types" />
  11. In assembly/__tests__/as-pect.d.ts add this

    /// <reference types="@as-pect/assembly/types/as-pect" />
  12. Edit the scripts in the package.json

    Remove the scripts values and have the below code instead. Leave everything else as is.

            "scripts": {
        "build": "yarn asb",
        "initialise:test": "yarn asp --init",
        "test": "asp --verbose -f unit.spec"
  13. In the terminal, go back to the project root folder to initialise git by running in root folder git init & touch .gitignore

  14. In the gitignore file add node_modules
  15. After all the above step your file structure should be similar to this

    │    ├──__tests__                                               
    │    │   ├── as-pect.d.ts          
    │    │   └── main.unit.spec.ts  
    │    ├──as_types.d.ts           
    │    ├──index.ts                
    │    └──tsconfig.json            
    ├── node_modules  
    ├── out         
    ├── .gitignore                 
    ├── as-pect.config.js            
    ├── asconfig.json               
    ├── package.json                 
    └── yarn.lock

Let’s add some sample code to test our setup (optional step).

  1. Create a simple call function getString on the smart contract, it returns the passed in string. Paste the code below into assembly/index.ts

     import { logging, Context } from "near-sdk-as";
     export function getString(str: string):string{
       logging.log(`${Context.sender} said ${str}`);
       return str;
  2. Add unit tests for the above function into assembly/__tests__/main.unit.spec.ts

     import { Context, VMContext } from 'near-sdk-as';
     import { getString } from '../index';
     const setCurrentAccount = (): void => {
       describe('', () => { 
       beforeEach(() => {
       it('returns the input string', () => { 
         expect(getString("hello world")).toBe("hello world", "should have returned the input string");
  3. Let’s test our smartcontract by running npm run test.

  4. Build the project by running npm run build. This would result in a .wasm file being added in out/release folder.
  5. To deploy into the d the newly compiled wasm file

     near dev-deploy <path to output wasmFile>

    e.g. in my case I ran near dev-deploy out/release/Near-AssemblyScript-Contract-template.wasm

    You can now call our smart contract function with near cli, you can read more on how to use near-cli here.

    You are all set!, you may now start building those awesome contracts — happy building 💫.


    Learn and Earn Near by enrolling in NEAR 101 course on Dacade.