1 files changed, 74 insertions, 0 deletions
diff --git a/public/projects/js-small-apps/bin2dec/app.js b/public/projects/js-small-apps/bin2dec/app.js
new file mode 100644
index 0000000..ccdaee0
--- /dev/null
+++ b/public/projects/js-small-apps/bin2dec/app.js
@@ -0,0 +1,74 @@
+function setErrorBox() {
+  const main = document.querySelector(".main");
+  const form = document.querySelector(".form");
+  const errorBox = document.createElement("div");
+  errorBox.classList.add("error-box");
+  main.insertBefore(errorBox, form);
+}
+
+function getErrorBox() {
+  let errorBox = document.querySelector(".error-box");
+
+  if (!errorBox) {
+    setErrorBox();
+    errorBox = document.querySelector(".error-box");
+  }
+
+  return errorBox;
+}
+
+function removeErrorBox() {
+  const errorBox = getErrorBox();
+  errorBox.remove();
+}
+
+function printError(error) {
+  const errorBox = getErrorBox();
+  errorBox.textContent = error;
+}
+
+function isValidInput(key) {
+  return key === "0" || key === "1";
+}
+
+function hasInvalidChar(string) {
+  const regex = /(?![01])./g;
+  const invalid = string.search(regex);
+  return invalid === -1 ? false : true;
+}
+
+function handleInput(value) {
+  if (hasInvalidChar(value)) {
+    const error = "Error: valid characters are 0 or 1.";
+    printError(error);
+  } else {
+    removeErrorBox();
+  }
+}
+
+function convertBinToDec(bin) {
+  let result = 0;
+
+  for (const char of bin) {
+    result = result * 2 + Number(char);
+  }
+
+  return result;
+}
+
+function handleSubmit(e) {
+  e.preventDefault();
+  const input = document.querySelector(".form__input");
+  const result = document.getElementById("result");
+  result.textContent = convertBinToDec(input.value);
+}
+
+function init() {
+  const form = document.querySelector(".form");
+  const input = document.querySelector(".form__input");
+  handleInput(input.value);
+  form.addEventListener("submit", handleSubmit);
+  input.addEventListener("keyup", (e) => handleInput(e.target.value));
+}
+
+init();