feat(solutions): add left-pad/javascript/function

challenges/left-pad/solutions/javascript/function/README.md

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+# left-pad/javascript/function
+
+Created by [@Divlo](https://github.com/Divlo) on 21 May 2023.

challenges/left-pad/solutions/javascript/function/package.json

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+{
+  "type": "module"
+}

challenges/left-pad/solutions/javascript/function/solution.js

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+import readline from 'node:readline'
+
+/**
+ *
+ * @param {string} string
+ * @param {number} resultLength
+ * @param {string} padString
+ * @returns {string}
+ */
+const leftPad = (string, resultLength, padString) => {
+  resultLength = resultLength - string.length
+  if (resultLength <= 0) {
+    return string
+  }
+  let pad = ''
+  while (resultLength !== 0) {
+    if (resultLength & 1) {
+      pad += padString
+    }
+    resultLength >>= 1
+    if (resultLength) {
+      padString += padString
+    }
+  }
+  return pad + string
+}
+
+const solution = () => {
+  console.log(leftPad(input[0], Number(input[1]), input[2]))
+}
+
+const input = []
+const readlineInterface = readline.createInterface({
+  input: process.stdin,
+  output: process.stdout
+})
+readlineInterface.on('line', (value) => {
+  input.push(value)
+})
+readlineInterface.on('close', solution)