TypeError in flex layout

[woutervs]

Describe the bug
which template:

MaterialDesignFrameworkModule — Material Design

A clear and concise description of what the bug is.

To Reproduce
schema: {
type: "object",
title: "Comment",
properties: {
name: {
title: "Name",
type: "string"
},
email: {
title: "Email",
type: "string",
pattern: "^\S+@\S+$",
description: "Email will be used for evil."
},
comment: {
title: "Comment",
type: "string",
maxLength: 20,
validationMessage: "Don't be greedy!"
},
contact: {
type: "object",
title: "Contact",
properties: {
firstname: {
title: "Firstname",
type: "string"
},
lastname: {
title: "Lastname",
type: "string"
}
}
}
},
required: [
"name",
"email",
"comment"
]
}

Expected behavior
No error should occur here

Desktop (please complete the following information):

• OS: Win10
• Browser Chrome/Edge
• Version Latest on both

Log output covering before error and any error statements

Uncaught TypeError: Cannot read property 'endsWith' of undefined
    at LayoutGapStyleBuilder.push../node_modules/@angular/flex-layout/esm5/flex.es5.js.LayoutGapStyleBuilder.buildStyles (vendor.js:89982)
    at DefaultLayoutGapDirective.push../node_modules/@angular/flex-layout/esm5/core.es5.js.BaseDirective2.addStyles (vendor.js:85516)
    at DefaultLayoutGapDirective.push../node_modules/@angular/flex-layout/esm5/flex.es5.js.LayoutGapDirective.updateWithValue (vendor.js:90190)
    at MediaMarshaller.push../node_modules/@angular/flex-layout/esm5/core.es5.js.MediaMarshaller.updateElement (vendor.js:88331)
    at SafeSubscriber._next (vendor.js:88421)
    at SafeSubscriber.push../node_modules/rxjs/_esm5/internal/Subscriber.js.SafeSubscriber.__tryOrUnsub (vendor.js:188363)
    at SafeSubscriber.push../node_modules/rxjs/_esm5/internal/Subscriber.js.SafeSubscriber.next (vendor.js:188301)
    at Subscriber.push../node_modules/rxjs/_esm5/internal/Subscriber.js.Subscriber._next (vendor.js:188244)
    at Subscriber.push../node_modules/rxjs/_esm5/internal/Subscriber.js.Subscriber.next (vendor.js:188221)
    at MergeMapSubscriber.push../node_modules/rxjs/_esm5/internal/operators/mergeMap.js.MergeMapSubscriber.notifyNext (vendor.js:193797)

Additional context
Problem only happens with nested objects seems so far

[woutervs]

Seems to be a problem in flex.es5.js when a function gets called with a null gapValue.
To resolve it I added the following code to 'flex-layout-section.component.ts':
this.options.fxLayoutGap = this.options.fxLayoutGap !== null ? this.options.fxLayoutGap : "0px";
in the ngOnInit() function right below this.options = this.layoutNode.options || {};

[bogdan-ardeleanu]

The issue seems to be very annoying for anyone who wants to integrate the current npm published version (1.0.4).
Can you try to push a fix for this issue into a new release version (let's say 1.0.5?)

[woutervs]

I've gone back to angular6-json-schema-form there seems to be more support there and it's upgraded for angular 7 as well.

The problem is there as well but we've figured out it's in the flexlayout package from angular, going back to using 7.0.0-beta.19 fixes it.
See angular/flex-layout#1011