mergePrimitiveObjects fails on GenericDeserializeInto

[rightisleft]

I'm attempting to use GenericDeserializeInto to merge A and B where certain fields on A have the exact same values of object B, both B has some newer fields.
Result:

Production Error:

TypeError: Cannot assign to read only property '0' of string 'base'
    at /Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:321:34
    at Array.forEach (native)
    at mergePrimitiveObjects (/Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:294:23)
    at /Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:308:36
    at Array.forEach (native)
    at mergePrimitiveObjects (/Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:294:23)
    at /Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:308:36
    at Array.forEach (native)
    at mergePrimitiveObjects (/Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:294:23)
    at deserializeObjectInto (/Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:350:16)
    at deserializeObjectInto (/Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:402:37)
    at DeserializeInto (/Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:438:16)
    at Object.GenericDeserializeInto (/Users/jmurphy/projects/ubq/api/node_modules/cerialize/dist/serialize.js:622:12)
    at ModelController.<anonymous> (/Users/jmurphy/projects/ubq/api/dist/src/ubq/controllers/models.controller.js:105:41)
    at next (native)
    at fulfilled (/Users/jmurphy/projects/ubq/api/dist/src/ubq/controllers/models.controller.js:4:58)
    at process._tickCallback (internal/process/next_tick.js:103:7)
Cannot assign to read only property '0' of string 'base'

iModelDTO = GenericDeserializeInto(req.body, DTOModel, iModelDTO);

Test Harness Error:

let payload: any = { items: {
    "alpha": ["dna", "chromatin", "core", "hmg", "particles", "nucleosome", "histones", "nucleosomes", "micrococcal", "nuclease"],
    "beta": ["cancer", "studies", "risk", "data", "lave", "analysis", "seskin", "osaka", "registry", "analyses"],
    "delta": ["dna", "sequence", "sequences", "gene", "cloned", "region", "genes", "cdna", "repeated", "coding"],
    "gama": ["dna", "sequence", "sequences", "mitochondrial", "human", "wheat", "rrna", "rdna", "cytosine", "cell"]
} };

class IStringTMap<T> { [key: string]: T; };
class IStringMapStringArray extends IStringTMap<string[]> {};

class Airport {
  @autoserialize items: IStringMapStringArray;
}

let lax: Airport = GenericDeserialize<Airport>(payload, Airport);
let san: Airport = GenericDeserializeInto<Airport>(payload, Airport, lax);

console.log( lax );
console.log( san );

TypeError: Cannot assign to read only property '0' of string 'dna'
    at /Users/jmurphy/projects/test_harness/node_modules/cerialize/dist/serialize.js:321:34
    at Array.forEach (native)
    at mergePrimitiveObjects (/Users/jmurphy/projects/test_harness/node_modules/cerialize/dist/serialize.js:294:23)
    at /Users/jmurphy/projects/test_harness/node_modules/cerialize/dist/serialize.js:308:36
    at Array.forEach (native)
    at mergePrimitiveObjects (/Users/jmurphy/projects/test_harness/node_modules/cerialize/dist/serialize.js:294:23)
    at deserializeObjectInto (/Users/jmurphy/projects/test_harness/node_modules/cerialize/dist/serialize.js:350:16)
    at deserializeObjectInto (/Users/jmurphy/projects/test_harness/node_modules/cerialize/dist/serialize.js:402:37)
    at DeserializeInto (/Users/jmurphy/projects/test_harness/node_modules/cerialize/dist/serialize.js:438:16)
    at Object.GenericDeserializeInto (/Users/jmurphy/projects/test_harness/node_modules/cerialize/dist/serialize.js:622:12)

Process finished with exit code 1

[rightisleft]

FYI:
I've swapped IStringMapStringArray for any, and i get the same results.