fields.js

var maps = {};

function extend( a, b ) {
	for ( var p in b ) {
		a[ p ] = b[ p ];
	}

	return a;
}

function createFieldMaps( renames, toFns, fromFns ) {
	var to = extend( {}, renames ),
		from = {};

	Object.keys( renames ).forEach(function( key ) {
		from[ renames[ key ] ] = key;
	});

	return {
		renames: renames,
		to: extend( to, toFns ),
		from: extend( from, fromFns )
	};
}

function mapFields( data, map ) {
	var field, value, mappedField,
		ret = {};

	for ( field in data ) {
		value = data[ field ];
		mappedField = map[ field ];

		// no map -> delete
		if ( !mappedField ) {
			continue;
		// string -> change field name
		} else if ( typeof mappedField === "string" ) {
			ret[ mappedField ] = value;
		// function -> merge result
		} else {
			extend( ret, mappedField( value ) );
		}
	}

	return ret;
}

maps.labels = createFieldMaps({
	addNewItem: "add_new_item",
	addOrRemoveItems: "add_or_remove_items",
	allItems: "all_items",
	chooseFromMostUsed: "choose_from_most_used",
	editItem: "edit_item",
	menuName: "menu_name",
	name: "name",
	nameAdminBar: "name_admin_bar",
	newItemName: "new_item_name",
	parentItem: "parent_item",
	parentItemColon: "parent_item_colon",
	popularItems: "popular_items",
	searchItems: "search_items",
	separateItemsWithCommas: "separate_items_with_commas",
	singularName: "singular_name",
	updateItem: "update_item",
	viewItem: "view_item"
});

maps.user = createFieldMaps({
	bio: /* string */ "bio",
	displayName: /* string */ "display_name",
	email: /* string */ "email",
	firstName: /* string */ "first_name",
	id: /* string */ "user_id",
	lastName: /* string */ "last_name",
	nicename: /* string */ "nicename",
	nickname: /* string */ "nickname",
	registered: /* datetime */ "registered",
	roles: /* string */ "roles",
	url: /* string */ "url",
	userName: /* string */ "username"
});

maps.author = createFieldMaps({
	blogId: /* string */ "blog_id",
	displayName: /* string */ "display_name",
	userLogin: /* string */ "user_login"
});

maps.post = createFieldMaps({
	author: /* int */ "post_author",
	commentStatus: /* string */ "comment_status",
	content: /* string */ "post_content",
	customFields: /* array */ "custom_fields",
	date: /* datetime */ "post_date",
	excerpt: /* string */ "post_excerpt",
	format: /* string */"post_format",
	id: /* string */ "post_id", /* readonly */
	link: /* string */ "link" /* readonly */,
	modified: /* datetime */ "post_modified",
	menuOrder: /* int */ "menu_order",
	name: /* string */ "post_name",
	pageTemplate: /* string */ "page_template",
	parent: /* int */ "post_parent",
	password: /* string */ "post_password",
	pingStatus: /* string */ "ping_status",
	status: /* string */ "post_status",
	sticky: /* bool */ "sticky",
	terms: /* struct */ "terms" /* array */,
	termNames: /* struct */ "terms_names",
	thumbnail: /* int */ "post_thumbnail",
	title: /* string */ "post_title",
	type: /* string */ "post_type"
}, {}, {
	post_date_gmt: /* datetime */ function( date ) {
		return {
			date: new Date( date )
		};
	},
	post_modified_gmt: /* datetime */ function( date ) {
		return {
			modified: new Date( date )
		};
	}
});

maps.postType = createFieldMaps({
	cap: /* struct */ "cap",
	capabilityType: /* string */ "capability_type",
	description: /* string */ "description",
	_editLink: /* string */ "_edit_link",
	excludeFromSearch: /* bool */ "exclude_from_search",
	hasArchive: /* bool */ "has_archive",
	hierarchical: /* bool */ "hierarchical",
	label: /* string */ "label",
	labels: /* struct */ "labels",
	mapMetaCap: /* bool */ "map_meta_cap",
	menuIcon: /* string */ "menu_icon",
	menuPosition: /* int */ "menu_position",
	name: /* string */ "name",
	"public": /* bool */ "public",
	publiclyQuerably: /* bool */ "publicly_queryable",
	queryVar: /* mixed */ "query_var",
	rewrite: /* mixed */ "rewrite",
	showInAdminBar: /* bool */ "show_in_admin_bar",
	showInMenu: /* bool */ "show_in_menu",
	showInNavMenus: /* bool */ "show_in_nav_menus",
	showUi: /* bool */ "show_ui",
	supports: /* array */ "supports",
	taxonomies: /* array */ "taxonomies"
}, {}, {
	cap: function( cap ) {
		return { cap: mapFields( cap, maps.postTypeCap.from ) };
	},
	labels: function( labels ) {
		return { labels: mapFields( labels, maps.labels.from ) };
	}
});

maps.postTypeCap = createFieldMaps({
	deleteOthersPosts: /* string */ "delete_others_posts",
	deletePost: /* string */ "delete_post",
	deletePosts: /* string */ "delete_posts",
	deletePrivatePosts: /* string */ "delete_private_posts",
	deletePublishedPosts: /* string */ "delete_published_posts",
	editOthersPosts: /* string */ "edit_others_posts",
	editPost: /* string */ "edit_post",
	editPosts: /* string */ "edit_posts",
	editPrivatePosts: /* string */ "edit_private_posts",
	editPublishedPosts: /* string */ "edit_published_posts",
	publishPosts: /* string */ "publish_posts",
	read: /* string */ "read",
	readPost: /* sring */ "read_post",
	readPrivatePosts: /* string */ "read_private_posts"
});

maps.taxonomy = createFieldMaps({
	cap: /* struct */ "cap",
	hierarchical: /* bool */ "hierarchical",
	name: /* string */ "name",
	label: /* string */ "label",
	labels: /* struct */ "labels",
	objectType: /* array */ "object_type",
	"public": /* bool */ "public",
	queryVar: /* string */ "query_var",
	rewrite: /* struct */ "rewrite",
	showInNavMenus: /* bool */ "show_in_nav_menus",
	showTagCloud: /* bool */ "show_tagcloud",
	showUi: /* bool */ "show_ui"
}, {}, {
	cap: function( cap ) {
		return { cap: mapFields( cap, maps.taxonomyCap.from ) };
	},
	labels: function( labels ) {
		return { labels: mapFields( labels, maps.labels.from ) };
	}
});

maps.taxonomyCap = createFieldMaps({
	assignTerms: /* string */ "assign_terms",
	deleteTerms: /* string */ "delete_terms",
	editTerms: /* string */ "edit_terms",
	manageTerms: /* string */ "manage_terms"
});

maps.term = createFieldMaps({
	count: /* int */ "count", /* readonly */
	description: /* string */ "description",
	name: /* string */ "name",
	parent: /* string */ "parent",
	slug: /* string */ "slug",
	taxonomy: /* string */ "taxonomy",
	termId: /* string */ "term_id", /* readonly */
	termTaxonomyId: /* string */ "term_taxonomy_id" /* readonly */
});

maps.file = createFieldMaps({
	name: /* string */ "name",
	type: /* string */ "type",
	bits: /* string */ "bits",
	overwrite: /* boolean */ "overwrite",
	postId: /* int */ "post_id"
});

module.exports = {
	to: function( data, type ) {
		return mapFields( data, maps[ type ].to );
	},
	from: function( data, type ) {
		return mapFields( data, maps[ type ].from );
	},
	array: function( data, type ) {
		var map = maps[ type ].renames;
		return data.map(function( field ) {
			return map[ field ];
		});
	}
};