尝试从 JavaScript 文件导入时找不到模块

Question

In my code, I have a directory for example named tree , and inside tree there are two js files tree.js and traversal.js .

The directory structure is like

/tree
  traversal.js 
  tree.js 

traversal.js

function inorderRecursive(root) {
    if (!root) return null
    inorderIterative(root.left)
    console.log(`${root.val} `)
    inorderRecursive(root.right)
}

function inorderIterative(root) {
    let curr = root
    let stack = [curr]
    while (stack.length || curr) {
        // if the current node exists, push it into the stack (defer it)
        // and move to its left child. Same as => inorder(curr.left)
        if (curr) {
            stack.push(curr)
            curr = curr.left
        } else {
            // otherwise, if the current node is null, pop an element from the stack,
            // print it, and finally set the current node to its right child. Same as => inorder(curr.right)
            curr = stack.pop()
            console.log(`${currNode.val} `)
            currNode = currNode.right
        }
    }
}

export {
    inorderIterative,
    inorderRecursive,
}

tree.js

import {
    inorderIterative,
    inorderRecursive,
} from "./traversal"

// and use it here

I referred import and export module from this , but when I execute the file, and the logs say

$ node tree.js

internal/modules/cjs/loader.js:883
  throw err;
  ^
Error: Cannot find module 'C:\Users\PC_1\desktop\algorithm\techie_delight\js-algo\tree.js'
?[90m    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:880:15)?[39m
?[90m    at Function.Module._load (internal/modules/cjs/loader.js:725:27)?[39m
?[90m    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12)?[39m
?[90m    at internal/main/run_main_module.js:17:47?[39m {
  code: ?[32m'MODULE_NOT_FOUND'?[39m,
  requireStack: []
}

Answer 1

You should definitely make a package.json with

npm init -y

and change the module type to es6 in the package.json file with

'type': 'module'

With this you essentially enable es6 import/export. And I would also add the file extension (.js) in the import statement like this

import {
    inorderIterative,
    inorderRecursive,
} from "./traversal.js"