#426 Priority-based Promise Executor

Design and implement a function runWithPriority that executes an array of tasks (functions returning promises) based on their assigned priority.

Requirements

• Each task is represented as an object: { fn: () => Promise<any>, priority: number }
• Tasks with higher priority should run before tasks with lower priority.
• If multiple tasks share the same priority, they should be executed in the order they appear.
• The function should return a promise that resolves with an array of results in the execution order.
• If a task rejects, the function should stop immediately and reject with that error.

Example

const tasks = [
  { fn: () => Promise.resolve('low'), priority: 1 },
  { fn: () => Promise.resolve('high'), priority: 3 },
  { fn: () => new Promise(res => setTimeout(() => res('medium'), 50)), priority: 2 }
];

runWithPriority(tasks).then(console.log);
// Output: ["high", "medium", "low"]

const failingTasks = [
  { fn: () => Promise.resolve('ok'), priority: 2 },
  { fn: () => Promise.reject('fail'), priority: 5 },
  { fn: () => Promise.resolve('skip'), priority: 1 }
];

runWithPriority(failingTasks).catch(console.error);
// Output: "fail"

Constraints

• Input is always an array of objects with fn and priority.
• Must not execute any lower-priority task until all higher-priority ones are finished.
• Handle empty input gracefully (resolve with []).