[Bug Report] Can not set the 12-hour time format in DateTimePicker

[forevist]

Element UI version

1.4.2

OS/Browsers version

Win10 / Chrome version 60.0.3112.90

Vue version

2.4.2

Reproduction Link

https://jsfiddle.net/pj71jkyw/

Steps to reproduce

Set fromat 'dd-MM-yyyy HH:mm a'
and try chose some date range

What is Expected?

i expect result like "16-08-2017 06:19 pm"

What is actually happening?

Actually look at the console, and you will see critical error: "TypeError: Cannot read property '0' of undefined"

because in "

element/src/utils/date.js

Line 251 in 463607f

fecha.format = function (dateObj, mask, i18nSettings) {

"

in fecha.format function (line 251)
we could see:
var i18n = i18nSettings || fecha.i18n;

but in i18nSettings

"

element/packages/date-picker/src/util/index.js

Line 6 in 463607f

const getI18nSettings = () => {

"

settings doesn't have amPm to convert like in code

(

element/src/utils/date.js

Line 206 in 463607f

a: [word, function (d, v, i18n) {

):

a: [word, function (d, v, i18n) {
var val = v.toLowerCase();
if (val === i18n.amPm[0]) {
d.isPm = false;
} else if (val === i18n.amPm[1]) {
d.isPm = true;
}
}],

[Leopoldthecoder]

Fixed in #6574