codesnips

error-handling

javascript 
// Creating a Promise
const myPromise = new Promise((resolve, reject) => {
  const success = true;

  setTimeout(() => {
    if (success) {

Promises and async/await patterns for asynchronous JavaScript

javascript promises async-await
by Alex Chang 1 tab
ruby 
class CreateDeadJobs < ActiveRecord::Migration[7.1]
  def change
    create_table :dead_jobs do |t|
      t.string  :jid, null: false
      t.string  :queue, null: false
      t.string  :klass, null: false

Background Job Dead Letter Queue (DLQ) Table

rails reliability background-jobs
by codesnips 4 tabs
typescript 
import axios from 'axios';

export type NormalizedErrors = {
  fields: Record<string, string>;
  formLevel: string | null;
};

Frontend: normalize and display server validation errors

ux typescript react
by codesnips 3 tabs
rust 
use anyhow::{Context, Result};
use std::fs;

fn load_config(path: &str) -> Result<String> {
    fs::read_to_string(path)
        .with_context(|| format!("failed to read config from {}", path))

anyhow::Context for adding error context without custom types

rust error-handling cli
by Marcus Chen 1 tab
ruby 
module ApiErrorHandler
  extend ActiveSupport::Concern

  included do
    rescue_from StandardError, with: :handle_standard_error
    rescue_from ActiveRecord::RecordNotFound, with: :handle_not_found

Structured JSON error responses

rails api error-handling
by Alex Kumar 1 tab
ruby 
class CircuitBreaker
  class CircuitOpenError < StandardError; end

  INCREMENT = <<~LUA.freeze
    local n = redis.call('INCR', KEYS[1])
    if n == 1 then redis.call('EXPIRE', KEYS[1], ARGV[1]) end

Graceful Degradation: Feature-Based Rescue

rails resilience circuit-breaker
by codesnips 3 tabs
ruby 
class Contract
  INVALID = Object.new.freeze

  COERCERS = {
    string: ->(v) { v.is_a?(String) ? v : v.to_s },
    integer: ->(v) { Integer(v.to_s) rescue INVALID },

Validated JSON Schema with dry-validation-style contract (lightweight)

api validation contracts
by codesnips 4 tabs
rust 
use std::collections::HashMap;

#[derive(Debug, PartialEq)]
pub enum LogLevel {
    Info,
    Warn,

Streaming Log File Aggregation With Buffered Line Iteration in Rust

rust streaming file-io
by codesnips 3 tabs
typescript 
export class AppError extends Error {
  public readonly statusCode: number;
  public readonly code: string;
  public readonly isOperational: boolean;

  constructor(message: string, statusCode = 500, code = 'INTERNAL_ERROR', isOperational = true) {

Backend: normalize errors with a single Express handler

express error-handling typescript
by codesnips 4 tabs
typescript 
export type Validator = (value: string) => string | null;

export const required = (message = 'This field is required'): Validator => {
  return (value) => (value.trim().length === 0 ? message : null);
};

Field-Level Form Validation with a Reusable useField Hook in React

react hooks forms
by codesnips 3 tabs
python 
from typing import Any, Optional

from fastapi.responses import JSONResponse
from pydantic import BaseModel

Consistent JSON Error Responses in FastAPI With a Custom Exception Handler

fastapi error-handling exceptions
by codesnips 3 tabs
python 
from marshmallow import (
    Schema, fields, validates, validates_schema,
    ValidationError, RAISE,
)
from marshmallow.validate import Length, Email, Equal

Field-Level Signup Validation in Flask with Marshmallow Schemas

flask marshmallow validation
by codesnips 3 tabs