Exercices CM 1

exercice4.js

@@ -0,0 +1,69 @@
+function readFile(path, charset) {
+  throw new Error("Function not implemented.");
+}
+
+function readTextFileIfExists(path) {
+  return new Promise((resolve, reject) => {
+    if (!path) {
+      reject(new Error("No file path provided"));
+      return;
+    }
+
+    readFile(path, "utf8")
+      .then(data => {
+        if (data.length === 0) {
+          reject(new Error("File is empty")); // explicit failure
+        } else {
+          resolve(data); // successful read
+        }
+      })
+      .catch(err => reject(err)); // I/O error
+  });
+}
+
+readTextFileIfExists("data.txt")
+  .then(text => console.log("File contents:", text))
+  .catch(err => console.error("I/O error:", err.message));
+
+try {
+  const text = await readTextFileIfExists("data.txt");
+  console.log("File contents:", text);
+} catch (err) {
+  console.error("I/O error:", err.message);
+}
+
+const files = ["file1.txt", "file2.txt", "file3.txt"];
+
+for (const file of files) {
+  try {
+    const text = await readTextFileIfExists(file);
+    console.log("File contents:", text);
+  } catch (err) {
+    console.error("I/O error:", err.message);
+    continue;
+  }
+}
+
+const otherFiles = ["does_not_exist.txt", "file2.txt", "file3.txt"];
+
+const failContents = await Promise.all(
+  otherFiles.map(readTextFileIfExists)
+);
+try {
+    failContents.forEach((text, i) => {
+      console.log("File contents:", text);
+    });
+} catch (err) {
+    console.error("I/O error:", err.message);
+}
+
+const successContents = await Promise.allSettled(
+  files.map(readTextFileIfExists)
+);
+successContents.forEach((result, i) => {
+  if (result.status === "fulfilled") {
+      console.log("File contents:", result.value);
+  } else if (result.status === "rejected") {
+      console.error("I/O error:", result.reason);
+  }
+});