transform csv file to 2D array

csv-to-array.js

/**
 * Transform CSV to a 2D array
 * @param {String} csvString
 * @param {String} [separator=,]
 *
 */
function csvToArray(csvString, separator = ',') {
    const sRegExp = new RegExp(`(^"|${separator}"|{linebreak}")(.*?)("${separator}|"{linebreak}|"$)`, 'g'); // matching field contents
    return csvString
        .replace(/\r/g, '') // remove part of window linebreak symbols
        .replace(/\n/g, '{linebreak}') // replace linebreaks
        .replace(sRegExp, (full, prefix, target, surfix) => {
            prefix = prefix.replace('"', ''); // remove prepended double quote
            surfix = surfix.replace('"', ''); // remove appended double quote
            return `${prefix}${
                target
                .replace(/{linebreak}/g, '{quotedlinebreak}') // replace inline linebreak(s) to preserve it when spliting
                .replace(new RegExp(separator, 'g'), '{comma}') // replace inline separator(s) to preserve it when spliting 
            }${surfix}`;
        })
        .split('{linebreak}') // construct 2D array, the first layer is seperated by linebreak(s)
        .map((v) => {
            return v
                .split(separator) // construct 2D array, the second layer is seperated by separator(s)
                .map((v) => {
                    return v
                        .replace(new RegExp('""', 'g'), '"') // replace double double quote(s) for CSV standard
                        .replace(/{comma}/g, separator) // retrive inline separator(s) preserved before
                        .replace(/{quotedlinebreak}/g, '\n'); // retrive inline linebreak(s) preserved before
                });
        })
}

// test
var csv = `
z,0,0.01,0.02,0.03,0.04,0.05,0.06,0.07,0.08,0.09
0,0.000 ,0.004 ,0.008 ,0.012 ,0.016 ,0.020 ,0.024 ,0.028 ,0.032 ,0.036 
0.1,0.0398 ,0.0438 ,0.0478 ,0.0517 ,0.0557 ,0.0596 ,0.0636 ,0.0675 ,0.0714 ,0.0753 
0.2,0.0793 ,0.0832 ,0.0871 ,0.0910 ,0.0948 ,0.0987 ,0.1026 ,0.1064 ,0.1103 ,0.1141 
0.3,0.1179 ,0.1217 ,0.1255 ,0.1293 ,0.1331 ,0.1368 ,0.1406 ,0.1443 ,0.1480 ,0.1517 
0.4,0.1554 ,0.1591 ,0.1628 ,0.1664 ,0.1700 ,0.1736 ,0.1772 ,0.1808 ,0.1844 ,0.1879 
0.5,0.1915 ,0.1950 ,0.1985 ,0.2019 ,0.2054 ,0.2088 ,0.2123 ,0.2157 ,0.2190 ,0.2224 
0.6,0.2257 ,0.2291 ,0.2324 ,0.2357 ,0.2389 ,0.2422 ,0.2454 ,0.2486 ,0.2517 ,0.2549 
0.7,0.2580 ,0.2611 ,0.2642 ,0.2673 ,0.2704 ,0.2734 ,0.2764 ,0.2794 ,0.2823 ,0.2852 
0.8,0.2881 ,0.2910 ,0.2939 ,0.2967 ,0.2995 ,0.3023 ,0.3051 ,0.3078 ,0.3106 ,0.3133 
0.9,0.3159 ,0.3186 ,0.3212 ,0.3238 ,0.3264 ,0.3289 ,0.3315 ,0.3340 ,0.3365 ,0.3389 
1,0.3413 ,0.3438 ,0.3461 ,0.3485 ,0.3508 ,0.3531 ,0.3554 ,0.3577 ,0.3599 ,0.3621 
1.1,0.3643 ,0.3665 ,0.3686 ,0.3708 ,0.3729 ,0.3749 ,0.3770 ,0.3790 ,0.3810 ,0.3830 
1.2,0.3849 ,0.3869 ,0.3888 ,0.3907 ,0.3925 ,0.3944 ,0.3962 ,0.3980 ,0.3997 ,0.4015 
1.3,0.4032 ,0.4049 ,0.4066 ,0.4082 ,0.4099 ,0.4115 ,0.4131 ,0.4147 ,0.4162 ,0.4177 
1.4,0.4192 ,0.4207 ,0.4222 ,0.4236 ,0.4251 ,0.4265 ,0.4279 ,0.4292 ,0.4306 ,0.4319 
1.5,0.4332 ,0.4345 ,0.4357 ,0.4370 ,0.4382 ,0.4394 ,0.4406 ,0.4418 ,0.4429 ,0.4441 
1.6,0.4452 ,0.4463 ,0.4474 ,0.4484 ,0.4495 ,0.4505 ,0.4515 ,0.4525 ,0.4535 ,0.4545 
1.7,0.4554 ,0.4564 ,0.4573 ,0.4582 ,0.4591 ,0.4599 ,0.4608 ,0.4616 ,0.4625 ,0.4633 
1.8,0.4641 ,0.4649 ,0.4656 ,0.4664 ,0.4671 ,0.4678 ,0.4686 ,0.4693 ,0.4699 ,0.4706 
1.9,0.4713 ,0.4719 ,0.4726 ,0.4732 ,0.4738 ,0.4744 ,0.4750 ,0.4756 ,0.4761 ,0.4767 
2,0.4772 ,0.4778 ,0.4783 ,0.4788 ,0.4793 ,0.4798 ,0.4803 ,0.4808 ,0.4812 ,0.4817 
2.1,0.4821 ,0.4826 ,0.4830 ,0.4834 ,0.4838 ,0.4842 ,0.4846 ,0.4850 ,0.4854 ,0.4857 
2.2,0.4861 ,0.4864 ,0.4868 ,0.4871 ,0.4875 ,0.4878 ,0.4881 ,0.4884 ,0.4887 ,0.4890 
2.3,0.4893 ,0.4896 ,0.4898 ,0.4901 ,0.4904 ,0.4906 ,0.4909 ,0.4911 ,0.4913 ,0.4916 
2.4,0.4918 ,0.4920 ,0.4922 ,0.4925 ,0.4927 ,0.4929 ,0.4931 ,0.4932 ,0.4934 ,0.4936 
2.5,0.4938 ,0.4940 ,0.4941 ,0.4943 ,0.4945 ,0.4946 ,0.4948 ,0.4949 ,0.4951 ,0.4952 
2.6,0.4953 ,0.4955 ,0.4956 ,0.4957 ,0.4959 ,0.4960 ,0.4961 ,0.4962 ,0.4963 ,0.4964 
2.7,0.4965 ,0.4966 ,0.4967 ,0.4968 ,0.4969 ,0.4970 ,0.4971 ,0.4972 ,0.4973 ,0.4974 
2.8,0.4974 ,0.4975 ,0.4976 ,0.4977 ,0.4977 ,0.4978 ,0.4979 ,0.4979 ,0.4980 ,0.4981 
2.9,0.4981 ,0.4982 ,0.4982 ,0.4983 ,0.4984 ,0.4984 ,0.4985 ,0.4985 ,0.4986 ,0.4986 
3,0.4987 ,0.4987 ,0.4987 ,0.4988 ,0.4988 ,0.4989 ,0.4989 ,0.4989 ,0.4990 ,0.4990 
3.1,0.4990 ,0.4991 ,0.4991 ,0.4991 ,0.4992 ,0.4992 ,0.4992 ,0.4992 ,0.4993 ,0.4993 
3.2,0.4993 ,0.4993 ,0.4994 ,0.4994 ,0.4994 ,0.4994 ,0.4994 ,0.4995 ,0.4995 ,0.4995 
3.3,0.4995 ,0.4995 ,0.4995 ,0.4996 ,0.4996 ,0.4996 ,0.4996 ,0.4996 ,0.4996 ,0.4997 
3.4,0.4997 ,0.4997 ,0.4997 ,0.4997 ,0.4997 ,0.4997 ,0.4997 ,0.4997 ,0.4997 ,0.4998 
3.5,0.4998 ,0.4998 ,0.4998 ,0.4998 ,0.4998 ,0.4998 ,0.4998 ,0.4998 ,0.4998 ,0.4998 
3.6,0.4998 ,0.4998 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 
3.7,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 
3.8,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 ,0.4999 
3.9,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.1,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.2,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.3,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.4,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.5,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.6,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.7,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.8,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
4.9,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.1,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.2,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.3,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.4,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.5,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.6,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.7,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.8,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
5.9,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 
6,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000 ,0.5000
`;

console.log(csvToArray(csv));