Cannot read properties of undefined (reading ('hash')

I am trying to write a simple blockchain in VSC on Windows 10. Running the node however results in an error that I cannot solve.

const SHA256 = require('crypto-js/sha256');

class Block {
    constructor(index, timestamp, data, previousHash = ''){
        this.index = index;
        this.timestamp = timestamp;
        this.data = data;
        this.previousHash = previousHash;
        this.hash = this.calculateHash();
    }

    calculateHash(){
        return SHA256(this.index + this.previousHash + this.timestamp + JSON.stringify(this.data)).toString();
    }
}

class Blockchain{
    constructor(){
        this.chain = [this.createGenesisBlock()];
    }

    createGenesisBlock(){
        return new Block(0, "01/01/2022", "Genesis block", "0");
    }

    getLatestBlock(){
        return this.chain[this.chain.lenght - 1];
    }

    addBlock(newBlock){
        newBlock.previousHash = this.getLatestBlock().hash;
        newBlock.hash = newBlock.calculateHash();
        this.chain.push(newBlock);
    }
}

let simCoin = new Blockchain();
simCoin.addBlock(new Block(1, "02/01/2022", {amount: 2 }));
simCoin.addBlock(new Block(2, "03/01/2022", {amount: 2 }));

console.log(JSON.stringify(simCoin, null, 4));

Yields this error:

C:\Users\simon\Desktop\Programmieren\Javascript\SimCoin\main.js:31
        newBlock.previousHash = this.getLatestBlock().hash;
                                                     ^

TypeError: Cannot read properties of undefined (reading 'hash')
    at Blockchain.addBlock (C:\Users\simon\Desktop\Programmieren\Javascript\SimCoin\main.js:31:54)
    at Object.<anonymous> (C:\Users\simon\Desktop\Programmieren\Javascript\SimCoin\main.js:38:9)

Where did I go wrong?

>Solution :

Apparently return this.chain[this.chain.lenght - 1]; is undefined.

Probably due to your typo, so re write:

return this.chain[this.chain.length - 1];