node.js: require json file returns MODULE NOT FOUND

Question

I'm trying to store a json array to a variable, but node.js return this error: { Error: Cannot find module 'jokes.json'

Here is my code:

let jsonData = require('jokes.json');
var jokes = jsonData.jokes;

The jokes.json file is in the same directory as the javascript file

Answer 1

If you just want the quick answer, you need to change to:

let jsonData = require('./jokes.json');

to instruct the nodejs module loader to look in the current module's directory for jokes.json. Yes, this is somewhat surprising to a node.js newbie, but there is some method to the madness (see below).

---

All the rules for loading modules via a relative path are described here: https://nodejs.org/api/modules.html#modules_all_together. I'd really suggest reading it.

To make it easier to discuss, I'll include a portion here:

require(X) from module at path Y
1. If X is a core module,
   a. return the core module
   b. STOP
2. If X begins with '/'
   a. set Y to be the filesystem root
3. If X begins with './' or '/' or '../'
   a. LOAD_AS_FILE(Y + X)
   b. LOAD_AS_DIRECTORY(Y + X)
4. LOAD_NODE_MODULES(X, dirname(Y))
5. THROW "not found"

LOAD_AS_FILE(X)
1. If X is a file, load X as JavaScript text.  STOP
2. If X.js is a file, load X.js as JavaScript text.  STOP
3. If X.json is a file, parse X.json to a JavaScript Object.  STOP
4. If X.node is a file, load X.node as binary addon.  STOP

LOAD_INDEX(X)
1. If X/index.js is a file, load X/index.js as JavaScript text.  STOP
2. If X/index.json is a file, parse X/index.json to a JavaScript object. STOP
3. If X/index.node is a file, load X/index.node as binary addon.  STOP

LOAD_AS_DIRECTORY(X)
1. If X/package.json is a file,
   a. Parse X/package.json, and look for "main" field.
   b. If "main" is a falsy value, GOTO 2.
   c. let M = X + (json main field)
   d. LOAD_AS_FILE(M)
   e. LOAD_INDEX(M)
   f. LOAD_INDEX(X) DEPRECATED
   g. THROW "not found"
2. LOAD_INDEX(X)

LOAD_NODE_MODULES(X, START)
1. let DIRS = NODE_MODULES_PATHS(START)
2. for each DIR in DIRS:
   a. LOAD_AS_FILE(DIR/X)
   b. LOAD_AS_DIRECTORY(DIR/X)

NODE_MODULES_PATHS(START)
1. let PARTS = path split(START)
2. let I = count of PARTS - 1
3. let DIRS = [GLOBAL_FOLDERS]
4. while I >= 0,
   a. if PARTS[I] = "node_modules" CONTINUE
   b. DIR = path join(PARTS[0 .. I] + "node_modules")
   c. DIRS = DIRS + DIR
   d. let I = I - 1
5. return DIRS

Because require('jokes.json') does not start with / or ., your require() statement goes to this:

4. LOAD_NODE_MODULES(X, dirname(Y))

which then calls

NODE_MODULES_PATHS(START)

which builds a list of search paths which includes the directory name from which the current script was loaded with an attached "/node_modules" sub-directory any global module install locations. It will not include the directory that the current module was loaded from.

Answer 2

if you are importing something custom module or file u have to require it below way (using relative path )

let jsonData = require('./jokes.json');

and for system module u can import this way const express = require('express')

if you create another module in ur folder name express and if you require it this way

const express = `require('./express')`

it will find ur custom express.js file not the express module