(babel plugin) Error: .sourceMap must be a boolean, "inline", "both", or undefined - babeljs

Question

When attempting to package a nuxt component, I get the above error. I am running nuxt 2.4.5, #babel/core 7.0.0 and rollup 1.4.0.
Does anyone have any thoughts?
Thanks in advance..
npm run script:
"build:es": "rollup --config build/rollup.config.js --format es --file dist/cxl-nuxt-map.esm.js"
Command :
nr build:es
cxl-nuxt-map#1.0.0 build:es /Users/userinfo/Projects/cxl-nuxt-map rollup --config build/rollup.config.js --format es --file dist/cxl-nuxt-map.esm.js
index.js → dist/cxl-nuxt-map.esm.js...
Stack Trace:
[!] (babel plugin) Error: .sourceMap must be a boolean, "inline", "both", or undefined
index.js
Error: .sourceMap must be a boolean, "inline", "both", or undefined
at assertSourceMaps (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/validation/option-assertions.js:65:11)
at Object.keys.forEach.key (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/validation/options.js:107:5)
at Array.forEach (<anonymous>)
at validateNested (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/validation/options.js:83:21)
at validate (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/validation/options.js:74:10)
at file (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/config-chain.js:174:34)
at cachedFunction (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/caching.js:33:19)
at buildRootChain (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/config-chain.js:120:36)
at loadPrivatePartialConfig (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/partial.js:85:55)
at Object.loadPartialConfig (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/#babel/core/lib/config/partial.js:110:18)
at Object.babel.loadPartialConfig (/Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/rollup-plugin-babel/src/index.js:80:20)
at /Users/dan.mahoney/Projects/cxl-nuxt-map/node_modules/rollup/dist/rollup.js:17051:25
at process.runNextTicks [as _tickCallback] (internal/process/next_tick.js:47:5)
at Function.Module.runMain (internal/modules/cjs/loader.js:804:11)
at internal/main/run_main_module.js:21:11
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! cxl-nuxt-map#1.0.0 build:es: `rollup --config build/rollup.config.js --format es --file dist/cxl-nuxt-map.esm.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the cxl-nuxt-map#1.0.0 build:es script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! /Users/dan.mahoney/.npm/_logs/2019-03-01T20_10_17_889Z-debug.log
Rollup.config.js:
/* rollup.config.js */
import vue from 'rollup-plugin-vue';
import babel from 'rollup-plugin-babel';
import commonjs from 'rollup-plugin-commonjs';
import postcss from 'rollup-plugin-postcss';
import replace from 'rollup-plugin-replace';
import { plugin as analyze } from 'rollup-plugin-analyzer';
export default {
input: 'index.js',
output: {
name: 'CxlNuxtMap',
exports: 'named',
},
plugins: [
postcss({
extensions: ['.css'],
runtimeHelpers: true,
exclude: 'node_modules/**',
}),
vue(),
babel({
exclude: 'node_modules/**',
}),
replace({
'process.env.INCLUDE_DEPS': JSON.stringify('false'),
}),
replace({
'process.env.NODE_ENV': JSON.stringify('production'),
}),
commonjs({
namedExports: {},
}),
analyze({ stdout: true }),
],
};

Answer 1

Found in the problem in my .babelrc file. The offending line was:
"sourceMap": "true",
should be:
"sourceMaps": true,