eia_si.gs

var SI_PREFIX = {
    '-24': 'y',
    '-21': 'z',
    '-18': 'a',
    '-15': 'f',
    '-12': 'p',
    '-9': 'n',
    '-6': 'μ',
    '-3': 'm',
    '0': '',
    '3': 'k',
    '6': 'M',
    '9': 'G',
    '12': 'T',
    '15': 'P',
    '18': 'E',
    '21': 'Z',
    '24': 'Y'
};

var E12 = [100, 120, 150, 180, 220, 270, 330, 390, 470, 560, 680, 820, 1000];
var E24 = [100, 110, 120, 130, 150, 160, 180, 200, 220, 240, 270, 300, 330, 360, 390, 430, 470, 510, 560, 620, 680, 750, 820, 910, 1000];
var E48 = [100, 105, 110, 115, 121, 127, 133, 140, 147, 154, 162, 169, 178, 187, 196, 205, 215, 226, 237, 249, 261, 274,
    287, 301, 316, 332, 348, 365, 383, 402, 422, 442, 464, 487, 511, 536, 562, 590, 619, 649, 681, 715, 750, 787, 825,
    866, 909, 953, 1000];
var E96 = [100, 102, 105, 107, 110, 113, 115, 118, 121, 124, 127, 130, 133, 137, 140, 143, 147, 150, 154, 158, 162, 165,
    169, 174, 178, 182, 187, 191, 196, 200, 205, 210, 215, 221, 226, 232, 237, 243, 249, 255, 261, 267, 274, 280, 287,
    294, 301, 309, 316, 324, 332, 340, 348, 357, 365, 374, 383, 392, 402, 412, 422, 432, 442, 453, 464, 475, 487, 499,
    511, 523, 536, 549, 562, 576, 590, 604, 619, 634, 649, 665, 681, 698, 715, 732, 750, 768, 787, 806, 825, 845, 866,
    887, 909, 931, 953, 976, 1000];

/**
 * Transforms the value to engineering units, for example: 1234 to 1.234kΩ
 * @param {4700} value The value to get transformed
 * @param {"Ω"} unit Optional unit, such as "Ω"
 * @param {2} significantDigits How many significant digits to show, default is 10
 * @returns {String} The input transformed, such as "4.7Ω"
 * @customfunction
 */
function WithPrefix(value, unit, significantDigits) {
    if (!unit)
        unit = '';
    if (!significantDigits)
        significantDigits = 10;
    var exponent = Math.floor(Math.log(Math.abs(value)) / Math.log(10));

    var prefix = false;
    do {
        if (exponent in SI_PREFIX && (true || (exponent % 3 === 0))) {
            prefix = SI_PREFIX[exponent];
        } else {
            --exponent;
            if (exponent < -24) {
                exponent = -24;
            }
        }
    } while (prefix === false);
    var result = (value / Math.pow(10, exponent));
    if (significantDigits)
        result = Number(result.toPrecision(significantDigits));
    if (prefix !== false) {
        result += prefix;

        return result + unit;
    }
}

/**
 * Transforms the value closest commercial value according to standard EIA, for example: 1234 to 1.2kΩ
 * @param {4700} value The value to get transformed
 * @param {"E24"} series EIA series, default is E24, supports E12, E24, E48 and E96
 * @param {"Ω"} unit Optional unit, such as "Ω"
 * @returns {string} The input transformed, such as "4.7k"
 * @customfunction
 */
function GetClosestResistor(value, series, unit) {
    var multiplier = 1;

    var standardValueList = [];
    if (!series)
        standardValueList = E24;
    else if (series === 'E96')
        standardValueList = E96;
    else if (series === 'E48')
        standardValueList = E48;
    else if (series === 'E24')
        standardValueList = E24;
    else if (series === 'E12')
        standardValueList = E12;
    else throw 'Invalid Series, should be "E24" or other';
    while (true) {
        if (value < 100) {
            value = value * 10;
            multiplier = multiplier / 10;
        } else if (value >= 1000) {
            value = value / 10;
            multiplier = multiplier * 10;
        } else break;
    }

    var closest = standardValueList.reduce(function (prev, curr) {
        return (Math.abs(curr - value) < Math.abs(prev - value) ? curr : prev);
    });

    var result = closest * multiplier;

    return result;
}

any chance this will be extended for the new prefixes (quecto, ronto; ronna, quetta)?

Hey @Not-A-Normal-Robot, as this is not a library, you can manually add the prefixes according to your needs when copying to your project 😄