Appending object values to string in javascript

Question

I have an array of object as below :

var filterConditionString = "";
var filterConditionsList = [
  {
    apiDataProperty: "LevelId",
    filterQueryParamName: "entityLevelId",
    value: 909
  },
  {
    apiDataProperty: "TypeId",
    filterQueryParamName: "entityTypeId",
    value: 910
  },
  {
    apiDataProperty: "WORKFORCE",
    filterQueryParamName: "filter1",
    value: 11
  },
  {
    apiDataProperty: "MAIN_INSTRUMENT",
    filterQueryParamName: "filter2",
    value: [112, 113]
  },
  {
    apiDataProperty: "MATRIX_ENTITY",
    filterQueryParamName: "filter3",
    value: [1131, 213, 413]
  },
  {
    apiDataProperty: "VERSIONID",
    filterQueryParamName: "filter4",
    value: 1141
  }
];

createFilterConditions(this.filterConditionsList);
console.log(this.filterConditionString);

function createFilterConditions(filterList) {
  this.filterConditionString = "";
  let separator = "",
    prevFilter = "",
    prevArrayFilter = "";
  filterList.map((filter) => {
    if (Array.isArray(filter.value)) separator = "||";
    else separator = "&&";

    if (filter.value) {
      if (Array.isArray(filter.value)) {
        filter.value.forEach((arrVal) => {
          this.filterConditionString =
            prevArrayFilter +
            `${filter.filterQueryParamName} == ${filter.value} ${separator}`;
          prevArrayFilter = this.filterConditionString;
        });
        if (this.filterConditionString.substr(this.filterConditionString.length - 2) == "||") this.filterConditionString = this.filterConditionString.substr(0,this.filterConditionString - 2 );
        this.filterConditionString = prevFilter + "(" + this.filterConditionString + ") &&"
        prevArrayFilter = this.filterConditionString;
        prevFilter = this.filterConditon;
      } else {
        this.filterConditionString = this.filterConditionString? prevFilter +`${filter.filterQueryParamName} == ${filter.value} ${separator}`: `${filter.filterQueryParamName} == ${filter.value} ${separator}`;
        prevFilter = this.filterConditionString;
        prevArrayFilter = this.filterConditionString;
      }
    }
    return this.filterConditionString;
  });
}

What I am trying to achieve is, the value of this.filterConditionString value should as below :

entityLeveId == 909 && entityTypeId == 910 && filter1 == 11 && ( filter2 ==112 || filter2 == 113 ) && ( filter3 ==1131 || filter3 == 213|| filter3 ==413 ) && filter4 == 1141

Points to be taken care of :-

1. if filter.value is not an array then filter[filterQueryParamName] should be separated by &&.

for eg :- entityLeveId == 909 && entityTypeId == 910

2. if filter.value is an array then only different values of same filter[filterQueryParamName] should be separated by || and other values of filter[filterQueryParamName] should be separated by &&.

for eg:- && ( filter2 ==112 || filter2 == 113 ) &&

let me know if anything is still unclear.

Answer 1

As Eknot already mentioned in a comment, your code is not very readable. I was not able to understand your code since it's way too complicated. You wrote your own steps down, why not follow them!

I wrote u a more readable example on how to do this. If you go through the code, you can see I did more or less the steps you described in your question:

function createFilterConditions(filterList) {

    // store all filters in an array
    const filters = []
    
    // helper for building up == chain.
    // keep it in one place!
    function condition(name, value) {
        return `${name} == ${value}`
    }

    // iterate the list!.
    for(let filter of filterList) {
        // read out used data.
        const name = filter['filterQueryParamName']
        const values = filter['value']

        // Step 1, if filter is NOT an array!
        // First to the simple values.
        // NO array?  Then store the condition!.
        if(Array.isArray(values) === false) {
            filters.push(condition(name, values))
        }

        // Step 2: If values is an array
        // Performance wise, it's probably not a big deal to check it twice. Generally prefer readability over performance.
        // Build up a condition Group joined with '||' separator and wrapped in parenthesis. 
        
        else if(Array.isArray(values)) {
            
            const sub_filters = []

            // add each sub value in the array!.
            for(let value of values) {
                sub_filters.push(condition(name, value))
            }

            // join the arguments together and wrap em in 
            // OR Operator ('||')
            const sub_condition = `(${sub_filters.join(' || ')})`

            // add the filter to filters array.
            filters.push(sub_condition)
        }
    }

    // Now, that all filters have been evaluated and normalised
    // it's needed to join ur whole group with ' && ' operator (and the space ofc..)
    // this is like step 3. In step 2 you are doing multiple things. 
    return filters.join(' && ')

}

I tested it and it works with your given data.

What i want to know from you, what do you use this for? .