A lightweight module to log objects as rows

This utility module exports two methods logRow(settings) for logging unstructured data as rows, and createTimer(autoStart) to capture time durations.

Installation

npm install log-row --save-dev

logRow(settings)

This method returns a function that takes one argument and formats the object based on the settings provided. See usage below.

Usage

const { logRow } = require("log-row");

const row = logRow({
  missingKeys: "None",
  defaultAlign: "right",
  separator: "  :  ",
  columns: [
    "Foo",
    { key: "foobar", label: "Foo", width: 6, truncate: true },
    { key: "animal", label: "Animal", width: 8, align: "left" },
    { key: "fruit", label: "Fruit", width: 8, pad: "·" }
  ]
});

console.log(row({ animal: "Cat", fruit: "Peach" }));
console.log(row({ animal: "Dog", fruit: "Apple", foobar: "hello world!" }));

The above usage will log the following.

Foo  :  Foo   None  :  Animal Cat       :  Fruit ···Peach
Foo  :  Foo world!  :  Animal Dog       :  Fruit ···Apple

settings

The logRow method returns a function, which when called will format the object passed in as a string using the column setting provided as below. The following also shows the defaults for each property.

const row = logRow({
  separator: " | ",
  missingKeys: null, // if set to string then all missing keys will be
                     // displayed with set value
  defaultAlign: "right",
  columns: [
    "foo" // each column entry can be string or object
          // strings will be printed as is
    { 
      key: "foo.bar",  // path from where to get the value on the object
      label: "FooBar", // is not provided key will be used as label,
                       // if set to null no label will be displayed
      width: 5,        // if provided column will be aligned
                       // to specified characters
      align: "right",  // defaults to the value specified for defaultAlign
      pad: " ",        // when width and align is specified the pad string
                       // will be used for alignment
      truncate: false  // value will be truncated to fit column
                       // width is set to true
    },
    // sepcify more columns here...
  ]
})

createTimer(autoStart = true)

This utility measures time. The autoStart (defaults to true) determines if the timer shoould start measuring as soon as initialized. The timer can be started and stopped multiple times by calling start or stop on the object returned. The object will measure only the running time.

Example

const { createTimer } = require("log-row");

async function foo() {
  const duration = createTimer(true); // timer started
  await someAsyncOp(); // takes 100ms
  duration.stop();
  await someOtherAsyncOp(); // takes 200ms
  duration.start();
  await someAsyncOp(); // takes 400ms
  console.log(`someAsyncOp took ${duration}ms`); // logs "someAsyncOp took 500ms"
}