How can I replace the tokens __fruit_type__, __clothing_type__, __fitness_equipment__, __meditation_app__ in collection.js with values from values.js?

I am trying to achieve this with the string.replace() Method

   collection.js

{
  "collection" : [
    {
      "fruit": "__fruit_type__",
    "clothings":{
      "item": "__clothing_type__}"
    }
  }, 
  {
    "fitness": "__fitness_equipment__",
    "mindfulness": "app called __meditation_app__"
  }
]
}

values.js

{
    "clothing_type": "winter",
   "fruit_type": "apple",
   "fitness_equipment": "treadmill",
   "meditation_app": "calm"
}

replace.js

const fs = require("fs").promises;

async function dataReader(filePath, data) {
  const result = await fs.readFile(filePath);
  try {
    return JSON.parse(result);
  } catch (e) {
    console.error(e);
  }
}
//read values
async () => {
  const value = await dataReader("./values.json");
  const clothing_type = value.clothing_type;
  const fruit_type = value.fruit_type;
  const fitness_equipment = value.fitness_equipment;
  const meditation_app = value.meditation_app;

  //read collection.json
  const data = await jsonReader("./collections.json");

  //replace tokens in `collection.js` with `values.js`
};

CodePudding user response：

USING REGEX !!

• Now you have a collection.json (like a template) file.
• And values.json (a filler for the template), which has a set of values that will be placed in the template (collection.json).
• We assume that keys of values.json file are the fillers in collection.json
• if a key in values.json is clothing_type then the placeholder is __clothing_type__
• We can now iterate through the keys of values.json and look for a match in the collection.json with two underscores in the prefix and suffix

///json will be parsed after filling the value
/// for this example i'll store the both the json files in varaible
const collections = `{
  "collection" : [
    {
      "fruit": "__fruit_type__",
    "clothings":{
      "item": "__clothing_type__}"
    }
  }, 
  {
    "fitness": "__fitness_equipment__",
    "mindfulness": "app called __meditation_app__"
  }
]
}`

/// naming the values.json as fillers as this may confuse with key,values in object
const fillers = `{
    "clothing_type": "winter",
   "fruit_type": "apple",
   "fitness_equipment": "treadmill",
   "meditation_app": "calm"
}`

function replaceFiller(template_collections,fillers){
    /// to loop through the keys of fillers or values.json we have parse this fisrt
    const fillersObj =JSON.parse(fillers);
    console.log(fillersObj);
    //// we dont want to modify the argument varaible "template_collection"
    /// so we will use a variable to store the template collection 
    /// and mutate them arbitrarily
    let resultJson = template_collections;

    
    /// looping through the keys of fillersObj
        for(let fillerKey of Object.keys(fillersObj)){
            /// here the filler key will be "clothing_type" ,"fruit_type" on every iteration
            // findig a match for the current key(fillerKey) with underscores in the collections.json and replacing them with the current keys value in fillersObj
            resultJson = resultJson.replace(`__${fillerKey}__`,fillersObj[fillerKey]);
            console.log(fillerKey,fillersObj[fillerKey]);
        }
  return JSON.parse(resultJson);
}
console.log(replaceFiller(collections,fillers));

Caveats

• Values. json folder should never consist of nested objects.
• I have also had the same task with nested objects as fillers; I had to write a lot of code to flatten the objects and then replace tokens.
• This code is fine for simple cases like this. If you are going to handle large objects, then use this library  jsonpath_object_transform