Basic cli loaders via process.stdout -- nodejs

README.md

Basic Nodejs Loaders

Use process.stdout to "rewrite" stdout and simulate a loader.

• Dots - basic ... loader
• Stars - animate an 8 frame circle loader
• Progress Bar - simulate % completion

dots.js

const main = async () => {
  cf = 0;

  setInterval(() => {
    let loader = (num) => {
      arr = [];
      for (let i = 0; i < num; i++) {
        arr.push(".");
      }

      return arr.join("");
    };

    process.stdout.cursorTo(0);
    process.stdout.clearScreenDown();
    process.stdout.write(loader(cf));
    if (cf >= 3) {
      cf = 0;
    } else {
      cf += 1;
    }
  }, 250);
};

main();

progress-bar.js

const main = async () => {
  total = 30
  cf = 0;

  setInterval(() => {
    let loader = (num) => {
      arr = [,">"];
      for (let i = 0; i < num; i++) {
        arr.unshift("=");
      }

      let prog = (num/total).toFixed(2).replace(/^0\.+/, '')

      if ((num/total) < 1) {
        arr.unshift(`[${prog}%]`);
      } else {
        arr.unshift(`[100%]`);
      }
      return arr.join("");
    };

    process.stdout.cursorTo(0);
    process.stdout.clearScreenDown();
    process.stdout.write(loader(cf));

    if (cf >= total) {
      cf = 0;
    } else {
      cf += 1;
    }
  }, 250);
};

main();

stars.js

const frames = [
  `
  ***
  *  
     
  `,
  `
  ***
    *
     
  `,
  `
   **
    *
    *
  `,
  `
     
    *
  ***
  `,
  `
     
  *  
  ***
  `,
  `
  *  
  *  
  ** 
  `,
  `
  ** 
  *  
  *  
  `,
];

const main = async () => {
  cf = 0;

  setInterval(() => {
    process.stdout.moveCursor(0, -4)
    process.stdout.cursorTo(0)
    process.stdout.clearScreenDown()
    process.stdout.write(`${frames[cf]}\r`)
    if (cf >= frames.length - 1) {
      cf = 0;
    } else {
      cf += 1;
    }
  }, 100);
};

main();