'coerce' does not execute for defaults

[nyurik]

There is no way to make coerce execute for the default value, yet there are some usecases where this would be very useful. Without this, coerce cannot be used, and argument has to be processed after parsing.

[nyurik]

Hmm, it seems like it does work, my mistake. Will submit a documentation PR.

[satazor]

@nyurik I've the same issue.. the coerce function is not called for the default value. How did you make it work?

[bcoe]

@satazor mind providing some code that reproduces; make sure you're on the most up-to-date yargs (we bumped a major) because we now apply coercion slightly differently.

[satazor]

@bcoe I am on yargs v6.

// coerce.js
#!/usr/bin/env node

'use strict';

const yargs = require('yargs');
const moment = require('moment');

const argv = yargs
.strict()

.option('min-commits', {
    type: 'string',
    alias: 'mc',
    default: '10:6M',
    describe: 'Filter results based on a minimum number of commits within a certain time-frame (format is <count>:<duration>, see http://momentjs.com/docs/#/durations/creating/ for the duration format)',
})

.coerce('min-commits', (arg) => {
    const split = arg.split(':');
    const count = Number(split[0]);
    const durationValue = parseInt(split[1], 10);
    const durationUnit = split[1].match(/([a-z]*)$/i)[1];

    if (isNaN(count)) {
        throw new Error('Invalid count specified for min-commits, format is <count>:<duration>');
    }
    if (isNaN(durationValue) || !moment.normalizeUnits(durationUnit)) {
        throw new Error('Invalid date when calculating the date for min-commits, format is <count>:<duration>');
    }

    return { count, date: moment().subtract(durationValue, durationUnit).toDate() };
})

.argv;

console.log('min-commits', argv.minCommits);

[satazor]

I'm currently using .check() to do what I want to do, though it doesn't feel right to mutate stuff in it.

[bcoe]

@satazor 👍 will dig into this.

[ssonal]

@bcoe I looked into this; seems the problem is with yargs-parser. Specifically, coercions are applied before defaults are set into argv. Happy to submit a pull-request that helps fix the issue.