Here’s my config in asconfig.json:
{
    "config": "flex",
    "compilerOptions": {
        "debug": true,
        "js-output-type": "flexjs",
        "source-map": true,
        "external-library-path": [
        "typedefs"
        ]
    },

    "additionalOptions": "-remove-circulars -js-output-optimization=skipAsCoercions",
    "files":
    [
        "src/PrintUIManagement.mxml"
    ]
}

tasks.json:
{
	// See https://go.microsoft.com/fwlink/?LinkId=733558
	// for the documentation about the tasks.json format
	"version": "0.1.0",
	"command": "asconfigc",
	"isShellCommand": true,
	"args": [
		"--flexHome=/Users/harbs/Documents/Apache Flex Dist/FlexJSNightly"
	],
	"showOutput": "always"
}

launch.json:
{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "NextGenAS Node.js Launch",
            "type": "node",
            "request": "launch",
            "program": "${workspaceRoot}/bin/js-debug/index.js",
            "stopOnEntry": false,
            "args": [],
            "cwd": "${workspaceRoot}/bin/js-debug",
            "preLaunchTask": null,
            "runtimeExecutable": null,
            "runtimeArgs": [
                "--nolazy"
            ],
            "env": {
                "NODE_ENV": "development"
            },
            "externalConsole": false,
            "sourceMaps": true,
            "outDir": "${workspaceRoot}/bin/js-debug"
        }
    ]
}

Flash Builder gives me an error when I try to compile.

Here’s my ant config (I copied and modified the files from the examples):

build.xml:
<project name="PrintUIManagement" default="main" basedir=".">
    <property name="FLEXJS_HOME" location="/FlexSDK/FlexJSNightly"/>
    <property name="example" value="PrintUIManagement" />

    <property file="${FLEXJS_HOME}/env.properties"/>
    <property environment="env"/>
    <property file="${FLEXJS_HOME}/build.properties"/>
    <property name="FLEX_HOME" value="${FLEXJS_HOME}"/>
    <property name="opt1_arg" value="-js-output-optimization=skipAsCoercions" />
    <property name="opt2_arg" value="-remove-circulars" />

    <include file="${basedir}/build_example.xml" />

    <target name="main" depends="clean,build_example.compilejs" description="Clean build of ${example}">
    </target>

    <target name="clean">
        <delete dir="${basedir}/bin" failonerror="false" />
        <delete dir="${basedir}/bin-debug" failonerror="false" />
        <delete dir="${basedir}/bin-release" failonerror="false" />
        <delete dir="${basedir}/target" failonerror="false" />
    </target>
</project>

build_example.xml:
<project name="build_example" basedir=".">

    <condition property="FALCON_HOME" value="${env.FALCON_HOME}">
        <and>
            <not>
                <isset property="FALCON_HOME" />
            </not>
            <available file="${env.FALCON_HOME}/lib/falcon-mxmlc.jar" type="file" />
        </and>
    </condition>

    <condition property="FALCON_HOME" value="${FLEXJS_HOME}/../flex-falcon/compiler">
        <and>
            <not>
                <isset property="FALCON_HOME" />
            </not>
            <available file="${FLEXJS_HOME}/../flex-falcon/compiler/lib/falcon-mxmlc.jar" type="file" />
        </and>
    </condition>

    <condition property="FALCON_HOME" value="${FLEXJS_HOME}">
        <and>
            <not>
                <isset property="FALCON_HOME" />
            </not>
            <available file="${FLEXJS_HOME}/lib/falcon-mxmlc.jar" type="file" />
        </and>
    </condition>

    <condition property="FALCONJX_HOME" value="${env.FALCONJX_HOME}">
        <and>
            <not>
                <isset property="FALCONJX_HOME" />
            </not>
            <available file="${env.FALCONJX_HOME}/lib/jsc.jar" type="file" />
        </and>
    </condition>

    <condition property="FALCONJX_HOME" value="${FLEXJS_HOME}/js">
        <and>
            <not>
                <isset property="FALCONJX_HOME" />
            </not>
            <available file="${FLEXJS_HOME}/js/lib/jsc.jar" type="file" />
        </and>
    </condition>

    <condition property="FALCONJX_HOME" value="${FLEXJS_HOME}/../flex-falcon/compiler-jx">
        <and>
            <not>
                <isset property="FALCONJX_HOME" />
            </not>
            <available file="${FLEXJS_HOME}/../flex-falcon/compiler-jx/lib/jsc.jar" type="file" />
        </and>
    </condition>

    <condition property="GOOG_HOME" value="${env.GOOG_HOME}">
        <and>
            <not>
                <isset property="GOOG_HOME" />
            </not>
            <available file="${env.GOOG_HOME}/closure/goog/base.js" type="file" />
        </and>
    </condition>

    <condition property="GOOG_HOME" value="${FLEXJS_HOME}/js/lib/google/closure-library">
        <and>
            <not>
                <isset property="GOOG_HOME" />
            </not>
            <available file="${FLEXJS_HOME}/js/lib/google/closure-library/closure/goog/base.js" type="file" />
        </and>
    </condition>

    <path id="lib.path">
      <fileset dir="${FALCON_HOME}/lib" includes="falcon-flexTasks.jar"/>
    </path>


    <target name="compilejs" description="Cross-compiles ${example}" unless="no.js">
        <echo message="Compiling ${example}.js"/>
        <echo message="FLEX_HOME: ${FLEX_HOME}"/>
        <echo message="FALCONJX_HOME: ${FALCONJX_HOME}"/>
        <echo message="GOOG_HOME: ${GOOG_HOME}"/>
        <property name="theme_arg" value="-define=CONFIG::theme,false" />
        <property name="extlib_arg" value="-define=CONFIG::extlib,false" />
        <property name="opt1_arg" value="-define=CONFIG::opt1,false" />
        <property name="opt2_arg" value="-define=CONFIG::opt2,false" />

        <java jar="${FALCONJX_HOME}/lib/mxmlc.jar" resultProperty="errorCode"
            fork="true">
            <jvmarg line="${mxmlc.jvm.args}"/>
            <jvmarg line="-Dflexlib=${FLEXJS_HOME}/frameworks}"/>
            <arg value="+flexlib=${FLEXJS_HOME}/frameworks" />
            <arg value="-debug=true" />
            <arg value="${theme_arg}" />
            <arg value="-compiler.mxml.children-as-data" />
            <arg value="-compiler.binding-value-change-event=org.apache.flex.events.ValueChangeEvent" />
            <arg value="-compiler.binding-value-change-event-kind=org.apache.flex.events.ValueChangeEvent" />
            <arg value="-compiler.binding-value-change-event-type=valueChange" />
			<arg value="-compiler.binding-event-handler-interface=org.apache.flex.events.IEventDispatcher" />
			<arg value="-compiler.binding-event-handler-class=org.apache.flex.events.EventDispatcher" />
			<arg value="-compiler.binding-event-handler-event=org.apache.flex.events.Event" />
            <arg value="${extlib_arg}" />
            <arg value="${opt1_arg}" />
            <arg value="${opt2_arg}" />
            <arg value="-js-output-type=FLEXJS" />
            <arg value="-closure-lib=${GOOG_HOME}" />
            <arg value="-sdk-js-lib=${FLEXJS_HOME}/frameworks/js/FlexJS/generated-sources" />
            <arg value="-external-library-path=typedefs"/>
            <arg value="${basedir}/src/${example}.mxml" />
        </java>
        <fail>
			<condition>
				<not>
					<or>
						<equals arg1="${errorCode}" arg2="0" />
						<equals arg1="${errorCode}" arg2="2" />
					</or>
				</not>
			</condition>
		</fail>
    </target>



</project>