generate_csv_and_download.js

// Desc: Produce CSV with client-side JS. Contruct Blob and Download as CSV file
let nativeCSV = ( ( _d )=>{
    let oCnt, jnCSV, sCSV, blCSV, elCSV;  //  config, json, array, blob, and element
    let retObj = {
        "init": ( _oCnt )=>{
            oCnt = _oCnt;
            if( oCnt.fileName.indexOf("####") !== -1) {
                oCnt.fileName = oCnt.fileName.replace("####", Date.now() );}
            jnCSV = sCSV = blCSV = elCSV = "";
            return retObj;
        },
        "setArray": ( _jnCSV )=>{  //  An array (rows) of arrays (cols) !jagged
            jnCSV = _jnCSV;
            if( oCnt.header ) jnCSV.unshift( oCnt.header );
            jnCSV.forEach(( aRow )=>{
                aRow.forEach(( sCol )=>{
                    if( typeof sCol === "string"){
                        sCSV += oCnt.delimQuote + sCol
                            .split( oCnt.delimQuote ).join("");
                        sCSV += oCnt.delimQuote + oCnt.delimCol;                       
                    }
                });
                sCSV = sCSV.slice(0, -1) + oCnt.delimLine;
            });
            return retObj;
        },
        "getBlob": ()=>{
            blCSV = new Blob([ sCSV ], { type: "text/csv;charset=utf-8;" });
            return retObj;
        },
        "createLink": ()=>{
            elCSV = _d.createElement("a");
            elCSV.setAttribute("href", URL.createObjectURL( blCSV ));
            elCSV.setAttribute("download", oCnt.fileName );
            elCSV.style.visibility = 'hidden';
            _d.body.appendChild( elCSV );
            return retObj;
        },
        "clickLink": ()=>{
            elCSV.click();
            return retObj;
        },
        "removeLink": ()=>{
            _d.body.removeChild( elCSV );
            return retObj;
        }
    };
    return retObj;
})( document );
// Usage: 
/*
console.log( nativeCSV.init({
"delimCol": ",",
"delimQuote": '"',
"delimLine": "\n",
"fileName": "graph_nodes_####.csv",
"header": ["id","name", "FQDN"]})
.setArray( currentGraph2Array(jCurrentGraph) )
.getBlob()
.createLink()
.clickLink()
.removeLink()    
);
*/

1. The resulting CSV files will contain a header row with deterministic column names.
2. The resulting CSV files will be quoted. Meaning each cell will be surrounded by double quotes.
3. Cell string data may contain a comma “,” however quotes will be removed.
4. Cell string data may contain only utf-8 characters.