Generate Code 128 barcode with 128B encoding

rebane_code128b.js

const c128bmap = [" ","!","\"","#","$","%","&","'","(",")","*","+",",","-",".","/","0","1","2","3","4","5","6","7","8","9",":",";","<","=",">","?","@","A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z","[","\\","]","^","_","`","a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z","{","|","}","~","DEL","FNC_3","FNC_2","Shift_A","Code_C","FNC_4","Code_A","FNC_1","Start_Code_A","Start_Code_B","Start_Code_C","Stop"];
const c128binmap = ["11011001100","11001101100","11001100110","10010011000","10010001100","10001001100","10011001000","10011000100","10001100100","11001001000","11001000100","11000100100","10110011100","10011011100","10011001110","10111001100","10011101100","10011100110","11001110010","11001011100","11001001110","11011100100","11001110100","11101101110","11101001100","11100101100","11100100110","11101100100","11100110100","11100110010","11011011000","11011000110","11000110110","10100011000","10001011000","10001000110","10110001000","10001101000","10001100010","11010001000","11000101000","11000100010","10110111000","10110001110","10001101110","10111011000","10111000110","10001110110","11101110110","11010001110","11000101110","11011101000","11011100010","11011101110","11101011000","11101000110","11100010110","11101101000","11101100010","11100011010","11101111010","11001000010","11110001010","10100110000","10100001100","10010110000","10010000110","10000101100","10000100110","10110010000","10110000100","10011010000","10011000010","10000110100","10000110010","11000010010","11001010000","11110111010","11000010100","10001111010","10100111100","10010111100","10010011110","10111100100","10011110100","10011110010","11110100100","11110010100","11110010010","11011011110","11011110110","11110110110","10101111000","10100011110","10001011110","10111101000","10111100010","11110101000","11110100010","10111011110","10111101110","11101011110","11110101110","11010000100","11010010000","11010011100","11000111010"]
function encodeCode128(text) {
    let code = "00";
    let checksum = c128bmap.indexOf("Start_Code_B");
    let checksumWeight = 1;
    code += c128binmap[checksum];
    for (let v of text) {
        const val = c128bmap.indexOf(v) < 0 ? c128bmap.indexOf(".") : c128bmap.indexOf(v);
        code += c128binmap[val];
        checksum = (checksum + val*checksumWeight) % 103;
        checksumWeight++;
    }
    code += c128binmap[checksum];
    code += c128binmap[c128bmap.indexOf("Stop")] + "1100";
    return code;
}
function renderCode128(text) {
    const result = encodeCode128(text);
    const canvas = document.createElement("canvas");
    canvas.width = result.length;
    canvas.height = 38;
    const ctx = canvas.getContext("2d");
    ctx.fillStyle = "#FFF";
    ctx.strokeStyle = "#000";
    ctx.fillRect(0, 0, canvas.width, canvas.height);
    result.split("").forEach((e,i) => {
        if (e == "0") return;
        ctx.beginPath();
        ctx.moveTo(i + 0.5, 0);
        ctx.lineTo(i + 0.5, canvas.height);
        ctx.stroke();
    });
    return canvas.toDataURL("image/png");
}