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@uqmessias
Created Dec 21, 2021
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Function to transform string into base64
/**
*
* @param {string} str
*/
function base64(str) {
const base64Characters = [
"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",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"+",
"/",
];
const binariesGroups24bits = str.split("").reduce((groups, c) => {
const ascii = c.charCodeAt(0);
const binary = ascii.toString(2).padStart(8, "0");
if (groups.length === 0 || groups[groups.length - 1].length >= 24)
groups.push(binary);
else groups[groups.length - 1] = `${groups[groups.length - 1]}${binary}`;
return groups;
}, []);
return binariesGroups24bits
.map((group) => {
const firstChar = group.substr(0, 6);
let secondChar;
let thirdChar;
let forthChar;
switch (group.length) {
case 8:
secondChar = group.substr(6).padEnd(6, "0");
break;
case 16:
secondChar = group.substr(6, 6);
thirdChar = group.substr(12).padEnd(6, "0");
break;
case 24:
secondChar = group.substr(6, 6);
thirdChar = group.substr(12, 6);
forthChar = group.substr(18).padEnd(6, "0");
break;
}
return [firstChar, secondChar, thirdChar, forthChar]
.map((char) =>
typeof char === "undefined"
? "="
: base64Characters[parseInt(char, 2)]
)
.join("");
})
.join("");
}
const input = "light work.";
const output = base64(input);
console.log(
`input: ${input}\n\noutput: ${output}\n\ndoes it work? `,
output === "bGlnaHQgd29yay4="
);
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