Bracketed property completion should escape string property name

[mjbvz]

TypeScript Version: 2.7.1-insiders.20180129

Search Terms:

• Bracketed property completion
• insertText

Code

const z = {
    '"': 1
}
z.

Accept suggestion for " on z.

Expected behavior:

const z = {
    '"': 1
}
z['"']

or

const z = {
    '"': 1
}
z["\""]

Actual behavior:

const z = {
    '"': 1
}
z["""]

Another example:

const z = {
    'a\nz': 1
}
z.

completes to:

const z = {
    'a\nz': 1
}
z["a
z"]